Bare flange type (not detachable ) towbar from P F Jones less than £80, depends if you need 7 pin or 13 pin type socket, and with CANBUS electrics you'll need a dedicated or a bypass relay, so you'll not get much change out of £130, leaving plenty for labour costs, but personally as it's an easy fit I'd do it myself. No need to remove or cut bumper and fitting time (towbar only) 30 minutes.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.