This fellow is always well recommended, not sure if he's still working. He is very thorough and no BS. (it's said sellers shudder if they hear his name!
Kenneth W. Rorison Marine, 250-655-3425, krorison at shaw dot ca
He might be on the pricey side, so check around if you like, but you may get what you pay for....
An in-water survey is really not ideal for a purchase survey. What's going on out of sight are some of the most important issues to investigate. So you do need to add the cost of a haulout unless there's an elevator accessible. Usually a 'half lift' is possible - ie they leave the boat in the slings over lunch to allow an underbody inspection, then splash the boat for the remainder of the survey. A pressure wash is really needed too to be sure you can see the whole picture. (If you buy the boat then you know it's clean and ready to go! Also if things are looking good at this time it's a good idea to change zincs if nec. while the boat's out)
btw, if you plan to insure the boat the carrier will likely require a survey in any event, for valuation purposes.
Welcome to the wonderful world of buying a boat (properly!)