Are you looking at £500 ($750) for everything? If so then buying the pieces is not going to be your best approach! There are some good buckets out there selling in the $200-$250 range, gaskets will run $300 (unless you go cloth which is $125), boots and gloves are roughly $170, armor is $800+. That being said, if you find a kit (that is 501st approval) for under $750, let me know, cause I'm in!
You're better bet is to pep it, there are some good files on the forums now (may check theRPF as well). It will definitely require a ton more work, but will keep your costs much lower (cardstock, superglue, resin and bondo are pretty cheap)! Good luck!