G4M is recommended quite a lot on the music forums I visit.
You might also like to have look at
Thomann Music's website, recommended to me by the friendly peeps on my bloke's drum forum (
http://www.mikedolbear.com/ ). They are based in Germany but they're a reliable, good quality retailer and are geared up for UK sales. I bought one of their own brand saxophones a year ago. Mega cheap, it will never be the Selmer or the Yanigasawa I really want, but it's good quality for the couple of hundred quid I paid for it and arrived within a week of ordering.