Sendclowns:
why was the school stopped from offering aerobatics on trial lessons? - more details please as this is a strange statement to make.
There are some organisations with AOCs who use non-FIs for aerobatic experience flights and corporate days but a number of flying schools offer aeros as part of a trial lesson (with an FI) - this is perfectly legal providing it is a genuine trial lesson, as I said earlier. We want to sell the freedom and excitement of flight - there's no better way than with aerobatics.
Please substantiate your comment "The twin would be clearly illegal" - why? where do the regs say this? (hint, you may spend a long time looking)
HFD