Graham
The tow bar is a Westfalia as supplied by Skoda parts and is detachable. The car did not come with pre fitted electrics so ALG did the whole thing including cutting the hole for the detachable flap. When not in use the ball has a designated position in the foam tray under the boot floor and is tidied away quite nicely. ALG fitted their little box of electrics which takes care of direction buzzing whe the indicators are on. If you are going down this road make sure you get the primer for the frame of the removeable flap as this is stuck on using pre fitted glue strips on the frame. The frame came off on my old Roomy after a few attempts of replacing the flap.
As a PS the lighting socket pushes up inside the hole and is therefore protected from the weather when not in use. This all seems rather verbal so I'll maybe post some pics if helps.
John