Hi, Keith.
I had this problem when I swapped the 'Van for a Swift with a 2004 Hitch Stabilizer, the Car is a Shogun, rear mounted spare Wheel with Stainless Cover. The answer is a combination of replies on here. In my case opening the rear door doesn't work, Jockey Wheel won't allow door to close.
The way I overcame this problem was with a spacer Plate between Tow Bar and Ball I have a Witter Bike Rack and the Car Plate for this combined with a spacer was just right. Here I must point out that using a spacer or Bike Rack might invalidate the Type Approval of the Bar. Mine was a Witter Bar and the additions were done by the original Fitter and confirmed as type approved. This still didn't give me enough room so I removed the Red Handle on the Stabilizer (2 Torx Bolts.) When Hitching up temporarily attatch handle without Bolts, raise stabilizer Arms, put Caravan on Tow Ball in usual way. Then using what is now a (detatchable) handle put Handle back on again without Bolts use Handle to apply tension to Stabilizer levers then remove Handle and put in Car. Just be careful using the loose Handle and guard against it slipping off as considerable force is required both when lifting and even more so applying pressure to the Handle.
Incidently more than Two Years after I started doing this Alko have brought out a Retro Fit for 25 Quid! which is basically the same procedure. My view is that so many people now use 4x4's with a Rear mounted Spare, that Alko should have predicted this problem at the design stage and the the upgrade should be free or at least on an exchange basis.
Eddie.