I was looking to fit a tow bar to my X5 and have found a westfalia with 13 pin electrics already fitted

Where is the best place to buy one? I've looked on ebay and prices seem to be £100+ second hand, is this the going rate for them? How much new from westfalia/ BMW?
Also, does the fitting on my photo look ok as it seems to have a notch cut out of it which I couldn't see on tow bar photos when looking at tow bars online.
Thanks in advance, Lee
