Is your local garage tried and tested? Indy LR garage? If this has only started since the new parts have been fitted, then as said above, it may well be the fitting...

The rear shoe setup needs proper adjustment otherwise it can drag. The internals have a few quirks in that the cables need to be in set mode, the shoes need centering, then adjusted, and then the drum/disc needs a good few taps while an allen bolt is slack to adjust the trailing side. 2011 MY D4 HSE
Previously 2001 D2 TD5, 1996 D1 300Tdi, 1985 90 2.2 petrol.
Bikes! KTM, BMW, British, Classics and others.

Here..this is a fantastic write up on Rear brake setup.
http://www.disco3.co.uk/gallery/albums/use...ssPics.pdf 2011 MY D4 HSE
Previously 2001 D2 TD5, 1996 D1 300Tdi, 1985 90 2.2 petrol.
Bikes! KTM, BMW, British, Classics and others.

Thanks Bardley,

Yes it's only happening since parts were fitted, no they are not specialist garage, just local to me and used them for years.

Looks like i maybe need to point them in the direction of your link

Cheers

UPDATE

as per my previous post, since fitting the genuine discs problems have gone away and stayed away. done over 1500 miles now and still no steering wheel wobble

to Advanced also, they issued a refund for Textar discs.