Phew! just found the bulletin that came with the loom.
Bulletin #0048; CDS Ref: R8492bu, Issue 2 dated 21/06/2000 ABS loom for vehicles upto VIN RJ 138975 with Traction Control. (hope this info helps others)
So now have ordered a new Genuine MG Rover SRB101301 ABS unit from Rimmers, hopefully the car will be restored to its former glory?
Computers and cars should never be mixed