Right, The problem was finally traced to the fact that Drivelink can't build racks for shit!!

After a good while to-ing and fro-ing, I got them to refund me the cost of the rack and the pump which was good of them.

If anyone is after a quality rack, I'd try AMK. The one I got off them was spot on first time

It took Drivelink 4 goes:

The 1st one was cockeyed and wouldn't fit the crossmember.
The 2nd had too much lock.
The 3rd was SUPPOSED to be my old one reconned, but sure as shit wasn't off any sierra I've ever seen!
The 4th one had the high spots and wouldn't return to centre on it's own.

Avoid at all costs!!

Neil.