The upper clyde is were you will catch the bigger grayling, there is grayling on most parts of the river. I really enjoy fishing the upper clyde, eg. Addington area.
If your looking to catch some good grayling you would be better fishing the clyde, there is grayling in the avon but not the same quality as the clyde.
john
Do we get aquatic threadworms in the UK?
One of the kids was poking at what i think was some kind of worm in a rain water puddle today, i've never seen anything like it before. It was about 1mm thick and 20cm long and a tan colour with a black tip.