Mark Roberston is a farmer by trade, he signed up to do PTC's airline program (zero to hero) a few years back, however as previous posts have stated he was unable to complete his CPL/ME and did not even get onto the IR course. As pilotbear states it was 'managed' to get him a CPL/SE!
Last time I looked, Monarch do not operate any single engine jet transport aircraft , so I think that may answer your question about his claim to be a pilot/captain with that or any other airline.
He has no airline experience (apart from as a passenger), nor does he have or ever passed a Multi engine rating nor an instrument rating!