Canoe Camping in SW Britain

This coming summer, I would dearly love to do some 2-night (friday/saturday)
canoe camping trips on rivers in the Devon/Cornwall regions. I will be in
Plymouth for some schooling, and will need access to a canoe (Indian-style,
not a kayak), paddling gear, and rivers that can be paddled by a skilled
class 2-3 open boater, with open shorelines for camping. I don't mind
portaging or crossing deadwaters, but I'd rather not spend the whole length
on the flats. I prefer moving water.

Do people DO that kind of thing in England? Are there boats and gear
available? And what rivers are recommended? The stretches of the Plym that I
saw last year seemed a bit boney.

Thanks, well in advance.

--riverman