Again welcome to Flyertalk hksinglon, welcome to the BA board. I hope when this is over you will also continue to participate in this Forum - and hopefully have some happier flying opportunities.

What I think has happened to your letter is that it has been sent to India for processing, and they either did not pick up your previous letter or were under so much time pressure that they didn't bother. Or a bit of both.

On the face of it you have a good case, also I guess BA didn't try to re-route you and even in the run up to Christmas I can't believe there weren't other options. Seeing the maintenance records is a red herring in my opinion, leaking equipment is not extraordinary, a long delay could easily have been avoided or reduced with more effort from BA.

So I'd send a short note back to BA saying "I don't believe you have read my second letter since you have simply resent your first reply. I would now like you to escalate my case for review. The circumstances behind the delay were not extraordinary and furthermore the airline could have greatly reduced my delay if reasonable measures had been followed up. If you do not confirm that you will pay my claim within the next 7 days I shall take further action without further notice, since I am unable to let matters rest there."