Not only the UK 500ft rule but the ICAO 500ft SARP - I'm not sure that any State files a difference.
However, this is Aerial Work which might be permitted in any State if a risk assessment had been carried out.
To state the blindingly obvious, a risk assessment would have this as a 'reasonably probable' outcome on the basis that most engines have a likelihood of failure of 1:100,000 flight hours. It might also be difficult to justify deliberately being in the HV curve with more than one occupant?
No, a twin would be twice as dangerous with a probability of failure of 2:100,000 and a similar outcome (unless it had OEI HOGE).
Jim