Jumping off a cliff

Watermeadow, of course you will do as you, and your estate agents / advisors think best. I'll just share our experience with you in case it is helpful:
A date for bis was set, 6 weeks after the plot was put on the market. Anyone expressing interest had to visit the plot, and be shown it by one of the vendors (I called it an 'interview'!). It was expressly stated that the highest bid might not be accepted.
On deadline day, the vendors went through and dismissed anyone they hadn't met and anyone they felt might be a 'developer'.
Of course, we could sell the house on tomorrow, and they would have no say, but they wanted someone who looked likely to stay for a good while, enter into community life and be a good neighbour. Of course, first judgements can be wrong - but they felt that by meeting prospective buyers they had lessened the chances of it being bought by someone who simply wanted to do a quick build and sell at a profit.

I'd like to add that the planning department and building inspector were extremely helpful throughout.

Yes, we have had that problem as well.

I once telephoned our local planning office to ask whether it was necessary to get planning permission for something - all I wanted was a yes or no answer. I was told I would have to send in a letter and pay a £50 fee before they would answer!

It seems your architects have agreed to work on a "no win, no fee" basis. This is unusual, but is allowed by the RIBA, providing the terms of engagement are set out in writing before the work starts.

Architects may charge on the basis of hours worked, a percentage of the estimated cost of construction, a fixed fee, on a percentage of "value added" or any other basis as long as it is clearly set out and agreed with the client.

In some cases the client may be given a choice. If things go well then an hourly rate may cost less, but in your case the architects are carrying the risk, and so this has to be taken into consideration. Planning appeals can be expensive.

This arrangement means that you have nothing to lose if planning permission is not awarded, but as you know, planning permission for a building plot adds greatly to its value. As you say, I'm sure your architects will do their very best to achieve the result you want.

Nannarose I assume I'll sell the plot, with PP, through an estate agent. If I get PP I'll then have just 3 months to sell and pay the architects so definitely won't be interviewing potential buyers!
MOnica this isn't an extension to my cottage, I'm hoping to sell a plot for a new house.
I've been warned about over-zealous conservation officers. I cherish the history of my cottage and don't want anything to spoil it's setting so the new house will match as far as possible.
I have had pre-application advice. As I'm not paying until I get PP I trust the architects to try very hard!

Planners are very cunning, or at least they are in our area. Planning applications for listed buildings are free, unlike any other planning applications. I think this is to stop people claiming the cost of planning was why they didn't get consent to replace wood window frames with plastic.

However, in our area,if you have a listed building, they effectively will not give planning consent unless you go have a pre-planning assessment first and for that you get charged.

The cost of planning permission is only a couple of hundreds of pounds, but architects fees for designing an extension and, with a listed building, other surveys that need to be undertaken if the house is listed, run into thousands.

We know, the cost of getting our hoped for kitchen extension designed and paying for the extra surveys that were needed, has cost thousands even before we get planning consent, although the pre-planning visit by the LA planners was very positive.

I wish you all the best watermeadow. Every day I am grateful to our lovely neighbours who did exactly that, and enabled us to build the house of our dreams.

Have you decided how you are going to sell the plot? Our neighbours wanted to have control over who lived next door, so they sold as a plot with planning permission, and 'interviewed' every prospective purchaser! Although there was no guarantee that the purchaser wouldn't sell on, they got a 'feel' for everyone who was interested- we were very lucky indeed.

If it is a money maker for you then go for it!

I didn't realise it was that much. Our friends applied but got turned down for what they wanted but an amended plan was approved - I wonder if they had to pay?

Presumably they did a pre planning application? This means that for a small fee, the planners will advise the designer of any likely planning objection, especially in a conservation area.
For example they might say that they would like to see a certain type of materials used, or that they would only consider a single storey building. This does not mean that plans will be passed or not, but is a useful indication to avoid pitfalls.

Architect often charge 10% of the value Luckygirl so I guess this is pretty valuable plot.

They're not their. I am literate honestly!

If their not going to charge till the application is granted you've got nothing to lose! Go for it?

£10K!!!! - faints quietly away! That's a lot! Good luck!