Yep, good points. There are other issues. Glasgow will certainly assist your holds. Busy airport means multiple holds at Erskine Bridge. Good for holding level altitude, sore on pocket.
CBN limited access to 'big airport' ATC and movements.
Prestwick can give best of both words. Not too busy, but still mixing with the bigger boys, and R/T with an international feel.
Yep Prestwick a must check.