207 towbar electrics

[TV200]

I've a 207SW which I wanted to add a towbar for tip runs and light towing. Due to the value fo the car, I may as well fit it myself - however looking at ebay its unclear whether I could just use a simple 7 pin lighting socket and join it to the rear lights, or whether I need a (far more expensive) dedicated bypass relay/ vehicle specific kit. I'd rather keep it simple and cheap, but don't want to do damage to the car.