I have to hand Pilot's Notes for the Hunter F4. There are probably considerable differences from the T7 but still probably quite relevant.
The very short section (87) on aerobatics reads:-
(a) Until experience is gained, the following speeds, in knots, are recommended:-
Roll 350 Loop 425 Roll Off 450 Vertical Roll 500.
(b) It is recommended that until experience is gained, loops are started in the height band 10,000ft to 15,000ft.
No , I have not inadvertently added a zero to the last two figures.
I'm not sure I would consider myself experienced on type with 43 hours over 4 years.
11 practices in 4 years is not experienced. I would do at least that many in a month and after 3 seasons displaying JP3 and JP4 still worked to a 500ft base and I still very nearly killed myself once. I did watch an experienced but under-practiced colleague do a Shoreham except he impacted in an empty field. I can recall the whole scene in slow motion. We nearly dropped the coffin there was such a weight of sand in it.
With his experience, I find it surprising that the pilot was happy to display at a small airfield surrounded by housing. Even more surprising, and much more worrying, that anyone would authorise such a display. It seems pure luck that the death toll was not massively greater.
Please can we forget all the irrelevant stuff about the takeoff, altimeter settings, blah blah blah. A pilot, inexperienced on type, lacking in practice, may well have made an error in a display which should not have been happening.