Mmm, ‘two day courses starting on a saturday’ eh. So working on the land at weekends when good folk should be resting following a week of graft, can’t see many takers for that to be honest? Saturday afternoons are for watching footie on telly, sunday mornings it’s church time, so basically it doesn’t leave a lot of time for digging your plot. Fitting a saturday morning and a sunday afternoon in (even allowing for presumably my payment at double bubble?) wouldn’t make me enough ‘brass’ for me to want to get in the motor and come to Macc twice in a weekend. Twice a year would be once too often! So I reckon you are on your own there ROF, you really need some out of work grave diggers, they work cheap! 
None of which has anything to do with sleeper cabs! 
Pete.