I have a copy of the very first newsletter distributed by Bristol Canoe Club.
This is “Issue 1, Number 1”, December 1962. The club had obviously been founded before this, but we don’t know how much earlier.
Note that this includes a suggestion to paddle the river Dart from Dartmeet in Jan 1963, “Rough water grading unknown, since, to the best of our knowledge, it has not been previously canoed, but probably R.W. III-IV.”
I have scanned this in, so have a look here.