Still holding the aircraft in stall, I would point out that the stick was fully back, but the nose wasn't pitching up - and THAT should be their recognition of the stall.
Sounds like a good demonstration. Having said that, it might be worthwhile warning the student that what works well in a Warrior may not necessarily work well in other types. For example:
From Pilots Notes for Mustang.RAAF Publication No. 780 date September 1950.
With fuselage tank full or half full, there is no buffeting to give warning of the approaching stall, but a series of stick reversals occurs just above the stalling speed; at the stall the right wing drops sharply, and unless immediate recovery action is taken, a spin may develop. If the control column is held back at the stall, a wing will drop very rapidly and the aircraft will become inverted.
Of course that is an extreme example as the student will never fly a Mustang, but it serves it's purpose to illustrate not all aircraft are as docile as a well maintained Warrior