G-VYGL went AOG in DLM due to a lightning and there being no A330 engineer in DLM to perform the inspection. As you mentioned, one 757 operated late last night and today's two flights brought the overspill pax from DLM.
G-VYGK will take over the A330 requirement for tomorrow May 22nd (MAN-TFS-MAN).
G-VYGL is expected back in MAN somewhere tomorrow afternoon to resume its duties on Monday.
G-VYGM is expected in MAN on the 25th to start operating alongside GL from the 26th.
Titan's G-ZAPX, currently in service for BA, will start operating for Jet2 from the 26th, based in Stansted (STN-PMI-STN-MAH-STN on its first day).