I'm back.
Tripped on the steps going down to the canoes and nearly went arse over t. The life preserver thingy was too small and came right up to my chin, and felt more like a neck brace. I nearly chickened out when the bloke gave the safety chat which seemed to be mostly, if you capsize just be sure to look after the canoe and don't lose the paddles. I involuntarily said Shite! very loudly on getting into the thing as I landed rather heavily into it and the whole lot seemed to be in danger of going under the water. Then we had a little run in with a pleasure launch who, after sounding off his horn several times had to come to a complete halt while we sorted out how to steer our way out of his path.
Apart from that, it was ok-ish. 
In fact I quite enjoyed it, all things considered. 
I would recommend it to anyone.