In this modern age, Single 13pin Socket with dedicated electrics is the way forward, either fully wired or part wired, depending on requirements, although the cost difference is minimal.
You'll eventually switch to 13-pin, so may as well start now. There's no "single / twin", and the pulgs are much better. Get the TT plug rewired to 13-pin while you're at it.
Sadly , I'm forced to drive shiny new cars as a work perk, so they all come 13-pin. I rewired my FC from twin-7 to 13 and haven't looked back since.
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.