Thanks all, the Battery is good & has been discharge tested at the battery centre. I have also been using a good second battery when the power drops from fault finding.
I have checked all of the fuses for continuity but I will go further & check the power going through the wiring from fuse 22 & the ECM Relay in the morning. From there I will check for power at the round plug wiring to the shift solenoid.
I don't see any mention of BMWs in the ALLDATA Website & the file i downloaded from eMANUALS does not contain Wiring Diagrams. Are there any other options apart from BMW.
Will see what tomorrow brings.