I couldn't face trawling through all the old posts, but here are the pictures of my 13 pin swivel mounting. Rear bumper removed for clarity (and I've only just collected my car from the body shop  ;D)
I have to say that despite there being a couple of holes for you to use to mount it, I couldn't find any suitable so that it could be hidden without fouling the lower edge of the bumper, so I welded it to the towbar (that's what the new black paint is on)
up out of site (or it would be if the bumper was fitted  ;))
http://i84.photobucket.com/albums/k17/Tiff4327/Omega/S73F1997.jpg

pulled down as in use.
http://i84.photobucket.com/albums/k17/Tiff4327/Omega/S73F1996.jpg

I might even paint the gubbins behind the plastic bumper ....... if it ever stops raining  :(

I was of the understanding that the 'bar fitted to TBBB (ex H21 ex AmigoMV6) which is now owned by The Daddy was an original fit VX one?  The electrics are swivel up out of sight.  Pull the plug down a quarter turn from stowed to in use, then pull downwards towards the ground to clear the detent then allow to spring loaded go back into stowed.  The bar itself is completely detacheable and able to be stowed in the boot.

I really liked it and use it quite a bit for towing Scout trailers and the like.  Pity I never took pics, perhaps TheDaddy could oblige?   :y 

hotel21 wrote on 16. May 2011 at 20:14:

I was of the understanding that the 'bar fitted to TBBB (ex H21 ex AmigoMV6) which is now owned by The Daddy was an original fit VX one?  The electrics are swivel up out of sight.  Pull the plug down a quarter turn from stowed to in use, then pull downwards towards the ground to clear the detent then allow to spring loaded go back into stowed.  The bar itself is completely detacheable and able to be stowed in the boot. I really liked it and use it quite a bit for towing Scout trailers and the like.  Pity I never took pics, perhaps TheDaddy could oblige?   :y

I have some somewhere. I took them with a view to copy it, but found this somewhat simpler set-up instead. When I explained the OE Bosal swivel plate, the bloke at Bosal hadn't a clue what I meant.  :-?

Ahaaaaaaaaaaaaaa! Thanks Andy that's a big help! I hadn't thought about it swivelling from the side, only front to back, but that makes sense. i think I'll fashion something similar. Thanks

geoffr70 wrote on 17. May 2011 at 14:08:

..., only front to back,  ......

that's how the OE Bosal towbar on Bruce's/Guy's old car was. A great set up but trickier to copy.  :y

Thanks Andy that's just the job for me also, likewise was about to attempt to design one to swing from back to front, never thought of side to side should be easier as thats where the most room is. :y :y

Try phoning Bosal at Bamber Bridge
http://www.bosal.co.uk/ABOUTBOSAL/BosalGroup/Contact/tabid/1012/Default.aspx he gave me mine foc  :y :y :y :y but I collected  ;)