It's Monarch with A320/319....
It was showing as an A319 on the timetable, which Monarch doesn't have (at least not at the moment).
VS3041 LHR0920 – 1020MAN 319 D
VS3043 LHR1610 – 1710MAN 319 D
VS3045 LHR2010 – 2110MAN 319 D
VS3046 MAN0650 – 0800LHR 319 D
VS3042 MAN1220 – 1330LHR 319 D
VS3044 MAN1750 – 1900LHR 319 D
Its Jet2 with a clapped out rotten B737 classic.....this is a rumour network after all.
Jet2's 737s have fully refurbished interiors,
they're very snazzy and red (if not particularly comfortable). The cabins are in better shape than some of BA's A319s. Would suit Virgin, but the service is listed as an A319 (see above).