A belated update (but made as soon as I was able to!).
Just returned to the UK after being away since mid-February. And, lo & behold my post includes a letter from LBHF cancelling the charge "at [our] discretion". I did explain that I'd be away for a while & asked them to update me by email which of course they didn't but hey ho, can't have everything!
A big thank you for your help.