THANK YOU so much for the advice. I tried looking for alternative part numbers on www.realoem.com and entered all my details and was doing fine until It asked me for my credit card details s ("no charge will be made now , during the free trial period"). I didn't understand what I was signing up for.... so didn't go any further
I Googled BMW dismantlers which produced a list my wife and I trawled through without success, I'm afraid
I've contacted BMW Customer services who were very helpful and promised to search themselves to see if they could unearth the part.
I'll try ECU Testing and Cartronics this afternoon, thank you.
The car is in very good shape (only 74,000 miles) , full service history from our local main dealers since new and new BMW parts fitted under the BMW Insured Warranty over the years.
We are worried about how a lack of Cruise Control would affect the price if we were to sell it .....
David