Well after a bit of messing around I have now got a fully functioning set of HID foglights.The transformation from those old yellow things is truly amazing and the difference in appearance with low beam on is quite stunning..all I need now is to track down a set of decent side light bulbs (think I have done that courtesy of link provided by ngrainqey last night )and the old girl will look great.
The most confusing bit of all was that I had to reverse the wiring at the original plug end of the fog light loom as it seems that original lights are switcehd by an earth and you require a switched positive to get the ballast to fire up,but other than that not too hard a retro fit.
Anybody thinking of doing the same should be aware that on the mini facelift and assume pre 1998 you will need to extend the black housing on the back of the lamps as the HID bulbs are too long for the original unit..this I did with the aid of an aerosol can cap which fitted perfectly and keeps the water out,sealed on with some gaffer tape and then feed the new wires from the bulbs out the back.Bit tight getting the lamps back into their mountings but jobs all done and well pleased as total cost was less than £60=00 all in.