I'm on site at Cranfield today - the evidence is that this may well be true.
The hangar is locked up, the airfield buildings are locked up with the blinds down, and there's a lot of milk uncollected on the doorstep.
I did my CPL and a few other bits with Bonus Aviation, and have on occasion had bits on a private aeroplane done by Bonus Engineering. In my experience they were whilst a bit disorganised at times, they've always been nothing but professional, never less than completely honest with their students, never took money up front - in other words they were most definitely not Cabair. If they have gone tits-up, then I have utmost sympathy with the staff, but at-least no students have been left high and dry as happened with a certain other company.
It will also leave Cranfield airport somewhat vulnerable - lacking both Bonus and Cabair, and with the BAe-146 increasingly operating elsewhere because of the poor services it got at home base, there's not a lot left. Certainly not to finance the Cranfield infrastructure.