Solicitor said there was less chance of that than winning a case against the sellers. They cover themselves with the small print, things like they can only examine what they can access on the day of the survey and adding in things saying if you are uncertain about something you should get a specialist in. But lets be honest who does that, you can't have electricians, plumbers etc going in and out testing everything even if you could find someone prepared to do it.
So you get something like the roof and they just go 'it wasn't raining the day we inspected so we wouldn't have seen any leaks'. It wasn't raining the day the plumber got in the loft to check the outlet pipe either but he managed to notice you could see outside though holes in the roof!
Survey done by the selling agent and some sort of warranty / insurance for even as little as 90 days would solve things. The people not up to the job would soon lose work if insurance companies had to start paying out to repair things they'd missed.