It's a common practice mate. We get customers who have just bought new floats off us and had towbars fitted with the 12 pin plugs elsewhere. They have the car on the road for only a few months and then things start going wrong. They bring it back to us assuming it's the float which I have a little module I made up I put on the floats to test everything to show them it's not the float. Then we check the car and there all scotch locked. We also put solder on the end of the plug wires so the screws crush onto the solder rather then the wire which gives a lot better connection.

Cheers Mick