As far as I am aware the only aircraft that MyTravel ever owned were the B757-200’s they got from the desert and the DC-10’S. All the others were / are leased.
Ah but Zante/Corfu/ routes are occupied by 320/321’s Rhodes is an A300 and Kos has passed onto XL. Could Monarch be planning on using the 757’s elsewhere such as LGW and LTN.