RAF Events, JHC and RNHF/RN all charge a display fee and a separate insurance charge.
The RAF events get NO discount for RAF displays.
The Army and Navy get 50% discount for RAF displays!
The insurance costs are attached to individual display aircraft/team. The RAF 'public' events are insured through a civilian broker at air show expense. This has to include lastminute.com cancellation costs, so you can imagine what sort of premiums are involved.
Insurance for every aircraft is on the FDD (Flying Display Director) Check-list of mandatory ticks in the box; along with DA, License, Medical etc.