Cats Five
Schleicher apparently declined the order for 70+ K21s. I reckon they would do that today, not wanting to devote their entire output to one customer for several years.
Yes I had heard that - But they might have gone for a smaller order to allow the Air Cadets to operate a mixed fleet.
Of course Schleicher might balk at any MOD modifications LOL - it would have to be a 'standard' airframe buy (I know Iknow - it'll never happen ! )
No problem operating a mixed fleet when they get their shiny new shed built - as a K21 is simplicity itself to maintain (as of course is a Grob acro
)