Like moosecf I was also on BA25 on 31 October in club. I applied for EC261/2004 compensation on the webform in the middle of November and BA rejected the claim for exactly the same reason as given by moosecf. Having read that BA have now decided to pay compensation for this flight I re-submitted the claim over the weekend and received .... exactly the same email as previously rejecting the claim. I suspect the likelihood of payment is linked to how far I'm willing to pursue in court so I guess this is the route I will have to look in to further.

I was actually fairly impressed by how quickly a hotel was offered at the airport (Sofitel), but was equally surprised that on a club ticket that BA hadn't proactively tried to rebook me onto another flight (by the time I got to the airport the BA27 was sold out in club (unsurprisingly) and there was apparently no availability left in business on CX). As the A380 was less than half full upstairs by the time the flight left the following morning I'm assuming that there was at least some degree of re-booking going on (although not for me!).

Will let everyone know how I get on.