blue frog is right, clx 27s and 18s will see you right,
www.gardinerpolesystems.co.uk, also im going to try,
www.thewaterfedpolecompany.co.uk, soon although i havent used them yet, they look good to me... the safe bet is gardiners they are generaly accepted now as the best poles you can buy, with them you get top notch afterservice as well.
forget all the big names you have heard of so far most of them are terrible, over priced, poor service crap products, the reason you will have heard of them is just becasue of their advertising budget :- )
familiarise your self with these types
Gardiner Pole Systems
thewindowcleaningwarehouse
pure freedom
some good trad offers - soap national
corwood and co or adapta - resin etc