This question was originally written by me in late January, just before a month away in Malta.
I got no replies, so I disconnected it anyway, and went away!
Just in case anybody else needs the answer to - "what happened?"
Nothing!
I put the battery back on when I returned, and everything started up OK.
In fact it took longer to insert the radio code than anything else!
So, don't worry, all the electronic "gizmo's" under the bonnet work OK, they don't lose memory, or anything.
This answer written on 24 June 2006.
John Simons, June 2006