The suggestion of the 300L was just that a suggestion I could just have easily suggested another type. The Extra was used at Oxford for BA Cadets to experience aeros and spins and those that I flew with enjoyed the experience. The French Air Force once used the CAP10 a fine aircraft.
As for the Tutor well it is broke, it is old, it has experienced serious airworthiness issues with the propeller, the RAF spin recovery checklist was not in alignment with Grob, we are no longer permitted to carry out flick manoeuvres, the Harness QRB failed and the width of the canopy arch makes lookout such a serious issue that the RAF fitted two collision avoidance systems.
The cost per flying hour?
Neither as yet have any crew successfully parachuted from an RAF Grob Tutor and I am not aware that the MoD or RAF ever carried out a full abandonment trial.
Tutor aerobatics are not very advanced when carrying cadets, we carry out a few basic options with a typical G loading 4G or less a bone dome is not helpful as they are heavy. As far as crashes go how many Tutor crash landings have occurred and how did the bone dome help if at all?
VFM value for money, not convinced the Tutor and the current system works well enough but funnily enough the old system with a Chipmunk did not kill any cadets while AEF flying and flew for decades under military management and engineering.