There are lots of Lakes/Mere's in Staffs and Shropshire with "big carp" in them, although I think you are setting your sights a bit high looking at 30plus as you have only just started fishing for only carp! Sorry if this sounds patronising, but wouldnt setting your sights on a 20lb fish be more realistic? (especially as 30plus fish are not that common).
In Staffordshire you have two lakes with 30's in them in the middle of Stoke on Trent. One I'm not going to mention as its busy enough but the other is Westport lake which I think has a scrapper 30 in it, but plenty of 20's. Busy water which is weedy but the female joggers certainly give you something to watch when the fishings slow.
Trentham Gardens in Stoke has some big fish but not sure how big and how you go about fishing it. Last I heard they were charging huge amounts for a syndicate.
Lots of club waters which give you the possibility of a 20 plus fish, it depends where you live and how far you want to travel.
I fished in Shropshire for the past few years. Beautiful waters..some big fish...but I'm still discovering different waters there myself.