Interestingly they used an A310-324 on the Weds flight which was a first visit as they usually use the -308s. I believe the -324s are configured differently, as well as being PW powered, and seat more so unless this was a one off to cover a tech issue maybe they are looking at more capacity.
I would be surprised however if they used 777s as they would be restricted off the LBA runway unless conditions were favourable. Maybe they'd be better looking at a lease on some 787s for this route!