Thanks for all the advice people, I have been without internet for a while now (rural France doesn't have much wifi kicking about, and when staying with friends theirs got taken out by a storm!!). So, to let you know...

The bike is now running and has been for 10 days now - the 2nd Honda dealer found some corrosion on the alternator which he reckons was stopping it from charging. He also reckons that the heated grips were killing it because they could stay on when he turned off the ignition, but given they're wired straight to the battery that's something of a feature... The controller for them was quite knackered though so it's possible it was causing issues, I never had hot hands when I didn't expect them but who knows, they're disconnected now cos it's SUNNY!!!! (this is a novelty, I've had far more rain than shine over the last few days).

I now have a multimeter, check the battery periodically to make sure it hasn't been running down it shows around 13v with the ignition off - is this normal on a 12v battery? Been going on the it's running and no issues so no tampering principle!

My mother has also been asking anyone she can think of near them who has anything to do with bikes, and we've found a guy who comes recommended, so I'm going to get him to check it over before I head off round eastern Europe (parents are in Paris and I'm with them for a week, so will also do some checking of my own).

And the amusing bit: the 2nd Honda guy also cleaned the bike cos he thought it was in desperate need, I didn't have the heart to tell him that by the time I'd got to that night's campsite in the rain it would be back to square one!!

Oh and Carole Nash provided me with a hire car while it was being fixed so I could carry on with the guidebook stuff, first time I have ever got my money's worth out of insurance!!!

Thanks again to all!

Laura