Homeguard:
If my memory serves me correctly I believe it was agreed that the AOPA aerobatic certificate was adequate demonstration of skill and a rating was not required. The course was decreased from 10 to 8 hours (and cubans/reverse cubans were removed from the syllabus) at the same time to make it slightly more accessible.
The FAA define aerobatics as a bank angle of more than 60 degrees and/or a fuselage attitude of +/- 30 degrees - a bit simplistic but it seems not unreasonable.
Sendclowns:
I assure you that there is no problem in selling aerobatic trial lessons so I'm not sure where you get your info from.
As an MEP instructor/examiner I can also confirm that the 70 hours is correct, but this can be on MEP and there is nothing to stop someone getting an ab initio MEPL. I would be interested in an ANO reference that forbids a trial lesson being taken/given in a twin (although I accept it's far from common practice, the only time I've done it is when the allocated aircraft has gone u/s and we haven't wanted to dissappoint).
FFF:
You saw the definition in an FAA document. I hope we're all agreed that only a fool flies an aircraft outside it's POH.
HFD