With both B733 gone shortly, the B752 going in April, and the remaining B736 on dry lease to Egypt, that leaves only 5 B738 and 2 B73W for the summer short haul. (off which I cannot see how the EDI/BCN/EDI will operate on Fridays), and 2 B763 on hire to the MOD, with 2 B763 for the long haul ops, there doesn't look to be any spare capacity this year.
In fact I am suprised GSM are not bringing in another B738, as if there are tech problems then they could be facing a difficult summer. Hoepfully tho using the newer aircraft they wont have as many problems as the B733/6 did the last few years.