Can anyone recommend some waterproof paniars I can carry on the back of my bike please? I'm looking for something that can hold quite a bit of stuff. Thank you.

Ortleib.

Vaude

How much is quite alot of stuff?
If you're really carying loads then maybe a trailer would be better for you than panniers?

Anyway, waterproof panniers, Ortleib. But I'd suggest that you wrap clothes and sleepig bag in a plastic bag anyway. If thats what you're carrying of course.

Ortleib is one possibility, although I'm going to recommend the better known Ortlieb.

:-)

(It's such a common typo that they've registered www.ortleib.de ;-) )

I personally tour with Karrimor panniers lined with a bin liner and covered with a rasta hat - works fine and a third of the price of Ortlieb/ortleib!

Thank you for your comments,How much is the Ortleib & Vaude bag please, and where can i get one?

Waterproof panniers should be just that waterproof, shouldn't need extra plastic bags.
Though I've not tried a trailer, I wouldn't have the extra expense was worth it. A decent set of waterproof panniers aren't cheap either, prob about £70 from memory.
Check out wiggle etc.