Good theory InOban.
For a couple of years, over the end july-Beginning Sep period, GLA would swap a 738 with a 733 from EMA, to help with Engligh summer hols. Maybe this year instead of that swap, they've just sent the entire aircraft down?
As to where it could go, could be any of the British bases (or all of them, if it operates 'W' Patterns)
Just a thought...