I am from a Carp and Pike fishing family and there are a few places in the South to go...
There are lots of places to go but you have to have a full fishing rod licence which you can obtain at your local post office or nearest council and usually you have to sign up to be a member of a Syndicate to fish in the good spots which can be pricey.....Most lakes have a bailiff (who are always good to get advice from) and some lakes are so private that you will get issued with your own gate key. Linear Lakes are good also there is one near Longleat called Shearwater (might need to check spelling of that one) which is a great place to go family fishing..There is a Centre Parks with pool etc..and you are near Longleat House and Longleat Safari Park..
Also you can join a Match Angling club where you are awarded points for quantity of fish, size and weight...and type...You can get points for Carp, Tench, Bream, Roach and Cat fish..you might catch the odd Pike but they try to segregate them into a different lake..
Fishing is ok here..and on the very odd occasion you get the whopper! My brother was fishing for Carp on the outskirts of London but managed to hook himself a 3 meter Cat Fish and ended up making the local News! lol!
Also..you have to remember that Carp fishing is fantastic in France! (fish are ridiculously huge) and thats only a little trip away in a boat..usually you are on the lake in a chalet
You should sign up to
www.carpforum.co.uk Loads of friendly fishermen to swap advice with..and some of them meet up in London and go for fishing trips in Europe as well....also some of the forum member make bespoke one off Rods ect... A good man based in Shirley near Southampton makes fantastic rods...I think his name is Mike Tunelley..he is on the Carp Forum.. They do also discuss other types of fishing on there as well..
I know a few people that recently came back from Barcelona..
There are some magazines you can subscribe to....These are the most popular..
Anglers Mail
Crafty Carper
Total Carp
Hope that helps