It is better value to do the rating in Canada. I did mine.. I have a professional seaplane licence...
Also, it is almost impossible to get a seaplane to rent solo as the insurance is so high. But the school in Canada (Nelson Mountain Air inc.) will hire the C180 on floats after you have 10 hrs.
This allows you to get some hrs in it and with the current exchange rates it works out at about £100-£120 hr .
Plus it is real mountain and lakes flying in some of the most spectacular scenery.