A2QFI, as far as I recall, the instruction to solo students on the Gnat was that we were to eject rather than attempt a forced landing. Anecdotally, there had been fatal accidents when students had tried to land flamed-out Gnats in the past. But we certainly practised them solo, to overshoot only. Obviously with an idling engine, hydraulic power was still available and we weren't authorised to practise manual PFLs solo.
On my FHT I was given a simulated engine fire and manual PFL into Mona - quite busy! Fire drill, STUPRECC and CUBSTUNT all to do all whilst trying to fly the PFL pattern.....
As an aside, we held a visit to the VC10 simulator for the Flying Club. That was when it was still managed by the RAF and a good time was had by all. We tried again after the creeping cancer of contractorisation had infiltrated the simulator - and were told that it wasn't in their contract....
So I'm glad that at least one tax payer was able to have a jolly in the Hawk sim - must have been great fun. And vastly better than that tiny little Gnat cockpit in a lorry which was the no-visual Gnat simulator.