Knock on delays caused by needing the maximum crew rest break between last nights LGW and this mornings LGW...
Whatever the issue BEs punctuality out of NQY has been a bit of a shambles really whether it's the E195 to LGW/MAN or the AT72 they seem to be sending in from BHX and onto STN.
I have noticed the extensions as you say. Presumably the DATCO takes a break between the normal closing time and the ETA of the last LGW rotation if delayed but I would imagine that 00:30 is far beyond the 10hour cut off for ATC and exceeds duty hours for RFFS as well.