How much should I charge?

Depends on whether it's going to be a once a year sort out or regular, say monthly.

I think he means regularly say monthly?

I am really picking a figure out of the air here but £20/30 an hour sounds reasonable as you be using your own home to do the work. I'm sure the accountant will be charging more than £100 per hour .

I would also say £20 - 40 per hour, depending on where you live. But make sure you time yourself and charge for all your time.

For simple bookkeeping such as this sounds £15 per hour is more than adequate.

When my mother retired she did this for a few local firms. With some she had a 'barter' system (not relevant to you in this situation). I used to live in an area that had a LETS system: www.letslinkuk.net/index.htm

If that doesn't work for you, I would look at local temp agencies to get a feel of what to charge. You will of course be VAT exempt, but will you pay income tax?

I would ask around a bit, to check he is OK, and if you get the feeling that he is, then be honest with him. With a figure in mind, ask what he thinks reasonable.

Maybe even ask if you could have a trial run off the books, say a couple of months' worth in exchange for something or other - something from his trade account at Screwfix, or a charitable donation if you support something.
That way there are no repercussions should it not work out. If it does, then you can formalise the agreement, as my mother did for some of her clients. She found it very rewarding and interesting.

Can you not get a guideline of the costs his accountant charges for this service then you can do a ball park figure that suits him and you, bear in mind that you are working in the comfort of your own surroundings and can work as and when you have the time,just do not under price yourself.

The rules are changing and everything needs to be 'digital' - I expect his accountant has told him that the carrier bag of receipts is not a service that he will provide going forward. I would make sure you're familiar with how it will work for the next tax return.
www.gov.uk/government/publications/digital-reporting-and-record-keeping-for-business-income-tax/making-tax-digital-for-business

The other side to working at home is that although you can work as and when you like and in comfort, you are also using your own heating lighting etc.

That's an interesting point Primrose If accountants are refusing to handle carrier bags of receipts, then smurf52 could corner the market and sell herself as a premium service.

I think trial run is the way to go - it will give you both an idea of what you are letting yourself in for. Also if it works, the job should become simpler once you've 'trained' him and got through the initial bags

Keep your fee to a amount that he can afford and you are happy with. That way he will continue to use you and you will have that regular income. If it’s something that you enjoy doing what a perfect way to earn a little extra without having to leave the house.

I did a similar thing years back while the family were small. At the time there were other people advertising a similar service so I simply looked at their charges then based my own on my individual situation. It's important to value yourself and your skills. My home insurer was told, no problems as far as I recall although when it came to renewal some wouldn't insure against theft by anyone I had invited in. Income tax liability needs to be calculated, if you pay tax it's reasonable to deduct a small amount for using home as office, i.e. an amount for utilities and cleaning if extra is incurred. Don't be deterred. There will be a lot of information on line. I think the idea of a trial run is a good one, that way either of you can opt out easily. In this case I would think about what you expect from the plumber, so how regularly you want to update records and make it clear you will not spend a sleepless 24 hours before his tax deadline. It can all be done gently and with humour, no need to be heavy handed but best to get the boundaries clear from the beginning. As I said, don't be deterred. It can be interesting and also a useful income supplement. Good luck with it.

I agree with the £20-£40 per hour but am wondering if he will still need a certified accountant to 'sign off' the annual accounts.

I think a lot depends on whether the dyslexia is compounded by laziness and chaotic record keeping. If he's kept everything in an orderly fashion, that's fine, but if the records are muddled or incomplete, you may not be able to make a proper job of this. You'd have to do a trial session first.

I think £20-£30 an hour sounds about right. It might be possible to barter for part of the work: say one or two hours' work in exchange for a boiler service?

What a great opportunity... and within your comfort zone...
I'd look at what the local market is offering/ charging and choose a middle figure... then discuss it with the plumber...flat rate or hourly? you may pay tax... your rate should accommodate that... get your taxes sorted out... probably self assessment... SAVE EVERY BILL and details of hours worked... ink for you printer etc and anything to offset your tax bill... make sure it is actually worth your time and effort...
Will be fun and you will have a new interest ... wish it was me... !
when we first retired we opened a B&B to get us used to the world of "non working" and being together 24 hours a day and we loved it... priced ourselves according to local prices and star rating... and blundered our way through for first couple of years until i got a grip... ha ha.
Enjoy.

For over 20yrs I ran a book-keeping and accountancy business after re-training in my 40's and working for a local chartered accountant for a few years. I retired finally last year handing my client-base over to a young friend. She charges £20/hour maximum. She uses a computerised system that allows her to send the draft year end accounts to their accountant by email. She does their payroll and Vat returns and works from home.
If anyone would like me to talk through what needs to be done to claim against tax for use of home as office, or easy computerised accountancy systems that are not expensive and in one case, is free, please get in touch. Am very happy to help.

What to do is call someone offering this service and ask what is the correct fee to pay

Grannyticktock, depending on severity, inability poor and chaotic record keeping is a result of dyslexia not laziness.
If he were to seek Access to Work assistance, the assistant would receive I believe about £17.50 per hour for 2 hrs per day. This might be a useful guide. If he has a proper diagnosis, does he know what he could claim free of charge to himself?

Chaotic record keeping is often no more than a trades person wanting to get on with the things they are good at without being bogged down by paperwork, accountancy, compliance and bureaucracy. There are still plenty people who hand over "carrier bags" of receipts to their accountants for them to sort through and put into some kind of order so I can definitely see the value of what you are being asked to do Smurf52 . If you are not going to be doing the full accounts (but just getting things in order ready for the accountant) and this is going to be above board and not a cash in hand transaction then I would think between £15 and £20 would be fair. Perhaps finding out what sort of turnover the plumber has will help you reach the right figure. Good luck.

Personally I'd find put what his hourly rate is for plumbing services and charge the same. I'm not one for valuing one skill above another just because you can

Thanks all. Food for thought. To clarify, the plumber still uses an accountant.

Can't agree with you there I'm afraid sharkgirl

shark his hourly rate will include all the overheads for running his business - the OP is going to have hardly any overheads

Up until recently I used to do this for my partner.
He used to walk in with bags full of receipts,it used to take me many evenings getting it in order I.e petrol, phone, materials etc etc then in date order after that.I asked a book keeper how much they charged and it was £25 per hour but that was working from an office with many overheads, so I would say between £15/£20 per hour. I did eventually start doing it monthly putting them straight into the relevant folders that I got all marked up. Soooo much easier.