G-LSAN is currently en route as LS155 from GLA to TFS. Unsure as to why/what a/c has gone tech, and why it has been left so long. The service is due into TFS approx 5 hours late.
Earlier, I noticed that ALC based airspare, G-GDFO was en route to TFS as EXS048A, to pick up the return flight as LS156. The Spanish base strategy has immensely reduced delays, by at least 3-4 hours on the LS156 sector tonight, and is due into GLA about 1.5 hours late. As you said, EU261...
Having the airspare in ALC is a great policy for EXS, however the plan is slightly flawed as it is only 148Y. In the Summer season most services will be operating full and a large proportion of the fleet is 189Y or 235Y. So there are frequently going to around 40 to 80+ PAX leftover who will have to wait for the aircraft operating the original service outbound from the UK or be returned on other carriers.