Thanks for all the replies lads, its great to hear all the different views out there. I notice that in the next edition of LRO international there will be an article on this very subject. Had a look at a couple of 90's and a 110 so far, the two 90's were fair (one was tidy enough), the 110 was a bit shabby, not a straight panel on it and the rear crossmember was rotten with holes appearing. I'm going to take my time and have a look at a few more before I take the plunge, will also have a look myself at a disco or two to make a fair comparison.
Marcus, I have a book by Ken Whitehead about pike fishing in general, he seemed to spend a lot of time on the Thames, fishing the weir pools as you say and also some of the tidal stretches too. Might be worth a look if you can find a copy. Happy hunting!