Codicil

My sister did this via a solicitor who charged her loads of money it would of been much cheaper to make a new will she realised afterwards.

I was charged £80 by a solicitor to add a codicil.

It was a lot more than that for my silly sister, ask the cost first

You do not need a solicitor to make up a codicil for you. You can write your own.
You should refer to the first will and the date that was signed. Then you put your additions or ammendments down on paper.
You need two witnesses to sign with their name, address, ocupation and date.
The witnesses should not be people who benefit from your will.
Then sign and date it yourself and KEEP it with the ORIGINAL will as they will eventually be looked at together.
Hope this helps.

That's absolutely great, thanks. It's only a small change.?