We paid £350, a couple of years ago for a fairly simple will from a good local firm of soliciters. They usually have at least one partner who is skilled in the ins and outs and can ask the right questions of you. It should be bulletproof with the concept of who the proceeds are left too if the next direct generation predecease the writer, are they shared between nephews and nieces etc. Do they go to to worthy causes. Try and reduce the wrangling amongst siblings etc.