I had performed the "Jog-unit installation" to ensure the RF receiver was not powered until I wanted to use the car and the days before flat battery increased from one and a half to a random time of anything from one and a half to four days. So, something was still drawing current at some times. Following the replacement of the drivers door-latch I am not hearing the random "thunk-thunk" of door lock cycling and things seem to be improved.
Early days for me yet, but I suspect the door-latch switches to have been causing me an issue. Will keep an eye on it and let you know.
@tomcat59alan Have you had any success with your door-switch investigations?