Tintagel is very Arthurian themeparkeque. Unfortunately the castle is in ruins and crumbling into the sea, so there's not a huge amount other than lots of tourist shops and the odd medieval display.
Glastonbury is a bit better with Arthur's grave and the Glastonbury thorn. Winchester has the round table, (actually dated to Edward III and given a paint job by the Tudors,) but still has a claim as Camelot.
Carlisle has a similar claim, so there's competing North/South heritage. Lots of places in the South West have some sort of Arthurian claim. Cadbury Castle being another Camelot.