Mark, I wasn't paying that close attention to what the LRA guy was connected to but he did have everything supplying back-up power (Disco4and power pack) connected directly to the terminals, nothing to the body or any other part of the car. He did say he was a bit surprised that the solar panel had been able to keep the battery topped up as he thought the battery monitor might have blocked it charging the battery. At one stage he had 3 different meters connected to different parts of the electrical system checking if the monitor needed resetting (apparently this needs to be done when the battery gets super-discharged) He also told me that in his experience since LR have started using some new style (as of 2010MY FFRR) battery made with what I heard to be glass(??) he had had far fewer self discharging batteries to deal with, if fact mine was only the second he had been called out for since the beginning of the year - the other was a Freelander2 that had been put in a garage and parked so close to the left hand wall of the garage that the owner couldn't get to the emergency keyhole to use the emergency key to get in after the battery had gone flat overnight on a brand new car!
Here is the cause of my problem - I suspect after 6 years of winding the charger cable to it's storage the moulded coupling at the connection to the panel has given up.
I'm not good with electrics but I assume that the battery was discharged by "earthing" through the flex touching the leather on the centre console.