Outcome: I sent a message back, politely querying the 10,000 as it was Club World on a long haul and got a phone call, just a few hours later, from a very nice chap in Customer Relations. He offered an additional 20,000 (so total of 30,000) which I accepted. That seems reasonable to me and it was nice to speak with a real person and to get the matter resolved quickly. At my request, he also reviewed another outstanding matter (a cancellation from 18 months ago, for which UK261 applies, and in reference to which I've sent a number of follow up messages), took some time to review old messages, confirmed that the matter had been incorrectly managed and agreed to resolve it, as he then did. So full marks to that helpful staff member.