Arfur-thank you.
This is how I understand current RAF display pilots would do it-The current Typhoon Display pilot is down to around 1000ft as his base height as I understand and is now practising over CBY. He's spent more than 6h getting there though (how many more I'm not sure)-and of course he has much better synthetic training aids than you probably had (or a civilian pilot would have).
And of course he flies the Typhoon as his day job....so no additional currency required either.
No trap intended-and what you say regarding the cost of doing all this for a civilian pilot....hence a balance needs to be found for civilian display pilots?