Hi Andy and Lesley,
Thanks for your concern. Glad you haven't had the hassle of change of airport. I gather that the change for my trip was because of British Airways and not Just You.
At least there was plenty of time to sort things and I had paid the extra £2.49 cancellation cover when I booked my original hotel at Gatwick. That meant I got the main expense back.
I have now repeated the exercise to secure a hotel and parking at Heathrow so am just keeping my fingers crossed that it won't switch back again.
In fact Heathrow is more accessible for me as I shall be travelling from Gloucestershire and won't need to approach the M 25!
Have a good time, both of you.
Mike