Managed to work that out eventually. What also seems to complicate my problem is that I could not log on in BMW mode to my other ECU Type NNN00830 (tried 20 times) This is Continental one from SAIC. I could get Learn EMS in ISO mode on SAIC so doubled back on tried ISO mode on Rover ECU NNN100743 and that worked, closed down and went back into BMW mode to get SAWS tuning option. Got update 042E on the way and all good.