This really is most unlikely.
All Leisure tried running an A320 in the mid 1990s and it was a disaster which was discontinued after one season, if I recall correctly. The same people still head that company and have done very well by focusing on what they do, which isn't running a charter airline.
Simply because a former director of Monarch has joined All Leisure doesn't mean that they are automatically about to launch an airline. The announcement was very clear - he is joining to run one of its cruise brands - and on the basis that bmi's Chief Operating Officer went to Royal Caribbean recently, does that mean RCCL are about to launch an airline too?