Well....I went out to bring the van up to the house for an injection of Mains Power, but before I started up I gave the Control Unit a severe talking to and tried again. Hey Presto! On it came
. I have switched on and off a couple of times to try and replicate the fault without "success"
I will still get in touch with Rex tomorrow as I intend paying him a visit at the end of the month anyway.
If I get an explanation for all this, I'll post it up at a later date.