It may depend on what the basis is on which you are contesting it. Are you claiming as a dependant under the Inheritance (Provision for Family and Dependants) Act 1975? Or are you challenging the authenticty of the will? Barmaid is the expert on these areas- hopefully she may see your thread.
You wait for Barmaid ! Probate, wills etc are her particular forte. I do know, from a claim in my family, that it can be a very expensive, and sometimes very long, business.
More than happy to assist if I can. However, I wonder if you could provide a little more detail so that I can target my answer at the specific facts rather than write you an open ended essay on the many different potential claims! Disguise the details/names etc, just a broad outline will do.
First make sure there is no clause in the will saying that anyone who contests the will automatically loses their share. This clause has been upheld in the past, where a woman lost at least a million pounds when she thought she should get more. She left court empty-handed, without even the measly million.