It is quite astonishing that the FDD 'was not provided with or was not aware of the display sequence.' Marry this up with what CAP 403 states about not doing ad-hoc and unrehearsed manoeuvres. The FDD would therefore not have known, could not have known, if he was or wasn't witnessing an impromptu manoeuvre or two. Granted, G-BXFI's routine may have been to script, perhaps a flawed script, but how can a FDD manage aerial safety if he doesn't know what the pilot is going to do?
Although Canada, Australia, USA and other display regimes are stated, South Africa has a rather onerous but simple system. Full written display sequences (entry height, speed, direction, linking manoeuvres and the whole nine yards) must reach the FDD well before the show. Then, all aircraft doing aerobatics must do a validation in front of the FDD - no validation, no display. And finally, all display pilots must personally attend a safety briefing by the FDD (often multiple briefings are held to accommodate those far away).
And finally, my hobbyhorse again: Ban downward vertical pull-through manoeuvres in high inertia jets. Had these been banned, this Thread wouldn't exist.