Final update:
Picked the car up from BW this afternoon, pump diagnosed as "burnt out" and replaced for the one I provided.
Coolant flushed and replaced.
Total bill £258 (3 hours labour and £20 + Vat for coolant)
Mechanics were all friendly and knowledgeable. The owner Jason was out of the country but his son Dominic dealt with me, the only negative thing I have to say is I did have to wait some time to be served as Dom was out collecting a part from BMW.
Asked for prices on my Insp 2 due at the end of the year £325 & £75 for a brake fluid change
All in all very happy to have paid a third the price of BMW and half that of the other local indy I have previously used and to finally enjoy a quick run for the first time in over a month
PS another coupe was also in at the same time for the same problem who also had the same pump as me. Chaps name is Gurps who had a ruby black 56 plate coupe with cream leather which was undergoing the work when I arrived..