Alarm RF Receiver Disco 2

Hi guys
carrying on from my posts reference BCU/key fob issues...I have replaced my RF receiver that transmits info from the key fobs. Ive had the vehicle plugged in & I either have a bad connection somewhere, water damage or a faulty BCU or all three; Autologic cannot connect to some essential areas of the BCU such as re-entering fob codes.
Before I buy a replacement BCU...
Does anyone have the knowledge to tell me which wire going to the receiver should be permanently live-Ive looked at a wiring diagram (with not much knowledge) & I think it should be Purple/Grey.
many thanks

For future ref-the Pink/Grey wire is the +12v supply from BCU to receiver-Black/Brown sends the signal back to BCU & black is obviously earth.
Thanks sent to a reliable source...