Everything that needed to be said has been said, only you can decide your course of action.
I would, however, insist on asking the seller why he think you had a survey done. If it was a final offer, why a survey at all? Precisely to identify potential pitfalls and, in this case, misrepresentation of the goods.
My house was built in 2000, and when we had a freshen up some norms had evolved (halogen ceiling lights, among others. When we sold my parents' Parisian flat, built in 1975, the surveyor identified that a complete rewiring was necessary because the norms had changed.
Ergo, I hate to think what needs to be changed in terms of wiring, plumbing (lead pipes anywhere?), etc.
All this to say that the seller cannot claim the house was maintained to the highest standards. Make the point to the estate agent, and rub their nose in it because they are the ones who advertised it as such.
And then decide as you see fit