You may be closer than you think. I know nothing about RAF operations or F-35, but in my previous work life was involved with the F-18 simulator at the manufacturer. One of the things that was done in our sim was developing flight demo routines to be flown by company test pilots. As I recall a long week was spent developing and practicing a display routine only a few minutes long with the demo pilot in the seat and a bunch of experts at the control station. Airshow routines for tactical aircraft are not casual exercises.