To close this story off, I'm reporting back with the end results.

Today, stirred up by the disappointment of my tequila being cancelled, I contacted BA to try and push things along with my claim for expenses during my HNL trip.

AA weren't really helping, they were simply going through the motions...please fill in a claim form (no link to the form provided, I couldn't find it), send ORIGINAL receipts here (wrong address in the USA), wait 8 weeks, blah blah blah.

A very helpful and competent BA customer service agent in the UK looked into the claim and telephoned me back to say that BA would pay my expenses IN FULL, no hassle, no jumping through AA hoops. Subsequently received an e-mail to say that they'll send the money to my account in the next 7 days.

Added to that they've credited 5,000 Avios for the poor service on BA2 (being left out of the meal service!).

I'm pleased that my claim has now been resolved and I can look forward to my next BA flights (alas not to Mexico!).