VW Electrics Rear fog lights
LHD to RHD fog light and ULO Hella differences in rear light cluster
Hacksawbob When you import a LHD van it will have the rear fog light on the left hand side, for the UK MOT your rear fog need to be either centre or right hand side. There are a number of ways to do this. One way is to wire a separate fog light that hangs of the back of the van and uses some or none of the existing wiring this is somewhat of a kludge. They look dreadful and typically the wiring is of questionable quality. but it will get you through the MOT  and is probably the solution an auto electrician will wire up if you ask one to do it for you. The neatest solution is to replace your LHD wiring with RHD wiring. If you can find an original RHD volkswagen loom and rear light bulb holders then you are set. be aware that there are two different types of bulb holder Hella and Ulo
Hella Vs ULO Simon Baxter from the Brickyard http://www.brick-yard.co.uk/forum/hella-to-ulo_topic16663.html
There are 2 brands of rear light for the T3 from the factory. Hella.or.ULO. There is no rhyme or reason as to what would be fitted to your van. Smoked lights only accept Hella bulb holders, infact all aftermarket lights I have seen accept the Hella version.If you want to fit alternative rear lights you will need to buy some Hella bulb holders.
The plugs are a direct swap and no mods are needed to change between Hella and ULO.
So if you have the whole RHD loom you swap it over and fit your cluster and away you go. f you dont have the RHD loom then you need to take the fog light feed from RHS to LHS.
Annoyingly the fog light contact is not available on the RH cluster on a LHD van so you either need a hella or ULO RHD cluster for your van.( Post a wanted advert or look for them on ebay they tend to go for £5-15.) OR modify your LHD bulb holders to work as UK spec. (more to follow) The colour coding for the fog light wire is Grey/White one way to do it without the loom is to unplug the Grey/white from the LH cluster by pulling the white plug and depressing the tang to allow it to pull out of the back of the plug. You can then make an extension to take it accross to the RHS. Ideally you will have a male crimp terminal for the RHS and a 6.3 mm uninsulated crimp terminal with tag  to push in to the white connector plug on the LHS.