The pond at Norwich is built up from ground level. So the bottom of the pond is essentially where your feet are, and a three foot high wall goes all the way around to contain the water. I've seen large models sailing there, but not as big as yours.
Other shows. Well the pool runs operate in 165ftx80ft at Brockwell and 100ftx60ft at St Albans, and depth varies between three to 9 feet. I think your boat would struggle in the smaller pool at St Albans to be honest, and I think you would find it impossible to get it through the building. Brockwell would be doable, as access is a little easier, but as you say, launch and recovery could be interesting.
There is the show at Alfold, fairly big lake, but the water looks completely opaque in pictures I've seen of it, so periscope running only I would think.
The lake at Barrow looks fairly well sized, quite a long way to travel though.
Maybe a good idea to build a smaller boat?