Dealer fit removable towbar?

When we ordered the SM there was only one price for the dealer fit removable towbar.

We haven't got the car yet so I'm assuming there is a different price for it if we'd taken it off the forecourt and took it back some weeks later to be done.

He said the price would still be the same (around £680 (forgive me but the paperwork is not infront of me)) whether we have the prep or not, although we would have to pay for the factory prep on top, another £170.

I have just had a quote from Chester Towing Centre to fit a Westfalia Swan-Neck Towbar (One small bumper hole as opposed to the hatch) complete with full 13 pin electrics using Skoda Parts (taken off the fuse box at the front) and ALL coding for TEPS, fog lights, reversing sensors etc etc £395 +VAT - not quite as cheap as Phil Taylor Towbars in Hampshire but a lot closer.. (A detachable one would add about £80 to the price)