I hope this will be helpful, in today's Daily Express, there was an advert for a firm of solrs who will do single Wills for £29.99, sorry I have not kept the paper but if you go out and buy one it was quite a large advert.
I saw a good solicitor in camberwell recently for anoter issue. I also asked about wills ans he quoted me £150 which i thought was reasonable. Christopher bernier at hartnells, 2 camberwell green (dont have number to hand). He was efficent in my dealings with him and i'll be returning there to do my will.