Hi Chris and welcome, I think £400 will be more than enough to get you up and running, just reading up about Candover and Bake lakes, Candover has some big old lumps in it, and Bake lakes is a combination of a number of lakes with specimen, tench, and fly etc etc, so a basic carp set up will more than sort you out, I persoanlly only fish with 2 rods, but you will be able to afford to fish 3 rods with your budget, go to you local carp/fishing shop and see the guys in there to set you up, Nash do some cracking carp rods on a budget with reels to match, and good bivvie for your night fishing, and then some bags and terminal tackle should set you up fine for most situations.
here is my local tackle dealer in Swindon and some of his prices which will give you an idea how much you will get for your £400: http://www.hinders.co.uk/cat/tackle/rods/carp-rods, and also http://www.fostersofbirmingham.co.uk/carp-and-barbel/rods/carp-rods, both are very very good suppliers of tackle for all budgets.
Good luck with it all and see you on the bank really soon