I had to cancel a pre-paid flight after leave had been approved - or rather my request had been timetabled, the actual bit of paper hadn't made it from someone's in-tray. Probably because they had also been away somewhere. The reason for the cancellation was 4 days (originally 36 hours) notice to go to the Islas Malvinas to do a non-job for 6 weeks. Despite my boss's best efforts (and a nicer bloke you couldn't hope to have as boss) - he even offered to pay for it from a discretionary fund - the blunt ones fought tooth and nail not to pay anything back. They wouldn't even accept that the on-line booking had been made and demanded a copy of my bank statement - which they didn't get. After a fight of over 12 months they grudgingly paid it back - but minus whatever the insurance premium from NAAFI would have been had I had that cover!
They have now lost any co-operation or flexibility on my part over leave plans. I put leave passes in good and early and will not change them unless it suits me.
Incidentally, a couple of years ago the AFPRB was critical of MoD failing to have a leave 'buy-back' system. But they haven't even mentioned it recently. However, along with the pensions issue I shall be asking about this when the AFBLT comes here soon. I understand that several people who haven't been able to take their leave have had approval to carry forward the extra over the automatic 15 days refused...... Personally I consider that they should have received 150% of a day's pay per diem in compensation.