No I am sorry but I dont agree with you. Yes you probably have a valid reason not to go on the March course, although I have seen others uproot everything in such a short time. The June course is another matter though, I am sure you could sell the holiday. If you were asked at the interview if you could join on the June course and you refused because of a holiday you had booked, I reckon "some" interviewers could have questioned your loyality. IMHO I dont think you would have got the job.