by nasty......i dont know what part of northants your`e from but a lot of the tackle shops especially in and around wellingboro do the club card.
i used to have a clubcard and the lakes your talking about is ringstead island.to get to them,all you do is keep following the lane that runs past the entrance to ringstead grange trout fishery.there is a gate blocking the entrance to the wellingboro waters and a key will need to be purchased to open it.
the two main pits there hold some cracking carp,tench,bream and pike etc....the back brook also holds good fish esp chub.the main river i think would also be worth fishing esp after some pre baiting.there is also some cracking roach fishing to be had near the loch as well.
there are plenty of other good waters to try as well and the wellingboro club card is quite good value for money.
if its day ticket fishing your`e after then you could try barnwell country park at oundle which holds some monster carp,big bream and tench as well!! you could also give blubell lakes a try at tansor (between oundle and peterboro).
corby boating lake also holds some carp over the 2olbs mark and thats availiable on a day ticket.
i know theres plenty more availiable but i aint got me thinking head on at the moment....its always a good bet to enquire at tackle shops.