Had some luck tracking down those fuel pumps on eBay. The pump for our car is the same as for the 1.8 Petrol Turbo cars, for proof see the Rimmer Bros links:
V8 - http://www.rimmerbros.co.uk/Item--i-GRID004174
1.8T - http://www.rimmerbros.co.uk/Item--i-GRID001966

The pump part number is WFX000290.

On eBay go to:
http://www.ebay.co.uk/itm/ROVER-75-M...53a52#payCntId

It doesn't list the V8, but the rover part number is correct.

I've ordered mine, nearly £100 less than Rimmers, so not too bad.

Ian