RICHinNC I imagine that if you had the correlating number of dives logged and at least some of your diving experience had taken place in a temperate/cold water environment they would have no problem letting you dive after giving you a brief on the local conditions.
As for fudging dive logs I imagine the best way to get around that is to have them all signed off by a buddy divemaster, or even better get the dive operator to stamp the log with their seal. I personally am a bit slack with my log-book, all it has is a list of the dives, who my buddy was, and a couple of other details like max. depth. on an excel spreadsheet. If I really needed too I could get the buddies listed to verify that I had done the listed dive/dives with them but there's no reason to go that far right now.
As for pt40fathoms - it's all relative mate.
If you train in 80f.+ degrees in board shorts with 100+ feet viz. and limited currents and then drop into 46f. degrees which is apparently what the ocean dropped down to this week, moderate currents and low viz. (which in Melbourne means 5-15 feet, the best viz. I've ever got here is 50 feet) ...80 feet at the bottom.. "you call that extreme, or even challenging"..
Welll, I never mentioned the word 'exteme', but for someone to have to deal with a 2 piece 7mm wetsuit for the first time, as well as the cold itself, along with everything else, I'm sure the change over would be considered a challenge.
I can see where your coming from though, we had a recent trip north of Sydney 2 weeks ago, and at the local dive store he said the water temp. was a chilly 66f. and that when we got to the dive site most people would be wearing dry-suits at this time of year
ut: I should pass on your Canadian dive holiday to them