Make your offer subject to survey.... if you come to an agreed price on that basis, then you won't 'blow' the survey fee without some idea that you will have a decent deal depending how that turns out.
I wouldn't pay for a survey on a boat that didn't have a prospective 'deal' in place. Any faults found on the survey can be used for renegotiation, since the original offer is subject to survey.
On paper, by your description it sounds like a decent boat for the money.. they have a good rep and have classic good looks..
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"