My LY flight is refundable (for a 130 fee which I'd happily swallow) but predictably having just spoke to BA there is absolutely no availability on LY for the next two weeks at all so that's a non-starter now. Looks like I will end up paying an extra 800 that I did not need to due to BA's call center teams not being up to date on their own policies, but at least I will make my trip. I shall make a complaint for the hope of a few avios but it seems the prevailing wisdom is that I won't be succesful for a claim to get a refund of what I spent on LY. Thanks to all for the advice.