Thanks for everyone’s comments.

Have also put in a claim with BA for the additional expenses incurred from buying new flights, hotel etc. Thought I would check the status of the claim earlier and the BA site didn’t recognise the case number (which they sent to me by e-mail). Doesn’t really instil much confidence…

(As an aside, had a similar claim with Swiss last year for a cancelled GVA to LHR flight. It took less than a week from making the claim to having the money in my account).