What sort of survey did you have? There are 3 sorts ranging from a surveyor having a quick look round to make sure the house is actually there, to a full structural survey which would be more comprehensive. I would get a 2nd opinion about the rewiring - the electrician might just be looking for some extra work. If you had a full structural survey, and the rewiring really does need to be done, you may have some recourse to the surveyor, but only if you had a full survey, and even then there will be all sorts of disclaimers on the survey that you will need to check. If you only had the cheapest survey, usually called a Home buyers survey, it probably isn't worth the paper it is written on. Good luck!