Nice write up! This needs to be on my to-do list. It's always encouraging to see explanations when problems get solved.

 

Confirming resoldering of relay pins on window ECU board solved my same rear window issue on my 97 D1. There is a video on youtube, just search "youtube rover window ecu". Also had door lock problems (would lock but intermittent/partial unlock), replaced little springs in lock actuators (door lock springs from UK guy on ebay, see other threads on doing this work, there are some good descriptions).