Stand 31L is designed for a/c up to B738, but isn't often used because the airlines prefer a front stand that doesn't need to be coached both ways. Stand 5 isn't large enough for a 738, and 30 is currently used for night-stopping Thomas Cook a/c.
As far as the Eastern and Western aprons are concerned, although they are mostly unoccupied during the day, they are very busy at night.
There are only two places I can think of which could accomodate a 738; at the rear of the Prestige hangar, although this may interfere with the Helimed operation, and the other is taken by a large purple aeroplane!
R5