+1 and ditto on all points in jkindredpdx's post.
Once you're at final selection stage of your yacht search, Survey is your chance to get beyond the "sales pitch" from the vendor and really find out the technical nitty gritty and vessel condition. Get in the crawl space and under the cabin
stows and locker lids as the Surveyor is inspecting. Ask Lots of questions.
Always get haul-out and test sail too, as part of the Surveyor's inspection
. If the vendor has any issue with these logistics, could there be an issue with the vessel?
Chances are the Surveyor may not pick up on everything, but you may in fact uncover more by asking "silly" questions. Additionally any issues the Surveyor finds go into a list for you to use in negotiating down the price.
Try and get a recommended qualified Surveyor, who is also certified by the Insurance company.
Edit: and disagree with colmj, you can always ask for privacy at any time during inspection. How else could you find all hidden areas and operate all latches
and systems on an unfamiliar vessel? There are some quite non-standard modifications out there!