I beleive that at least G-CELG is ALC now, and in the summer, there is often another down there. ALC is an ideal base, 2 hours from the UK, 2 hours from the farthest destinations. I believe that Jet2 have their own crew down in ALC, though I am not sure, but this is likely as they have their own baggage handlers, passenger service assistants, and sales team down there