Another +1 for the Ultra Jazz from DiMarzio. I put a pair in an old 5 string squier and it transformed the sound. f you want to spend even less money and end up with a pair of hot, clean J pups then GFS ones are ace. I've got a pair in my fretless 'bitsa' jazz bass and it sounds incredible. You'll probably have to import them from the states, but even once you take that into account then they're still really good value for money.
http://www.guitarfetish.com/GFS-JB-Pro-Jazz-Bass-Style-Alnico-Pickups_p_318.html
currently $60 for a pair, which I think is about £47. No brainer.