Hughes, An article 86 permission requires 42 days notice to display. This also covers special events too". Private gatherings(like weddings can be conducted without a permission - provided there is no advertising to the public (including those attendees associated with the wedding).
NOTHING, repeat NOTHING - allows any aircraft to fly within 150m (except for take off and landing only) of persons, vehicles, structures, vessels (knowingly). You also cannot overfly a property where it is known there are inhabitants.
* An exemption to this SERA 5005(f)(2) rule can be made on safety grounds. Or if applying for an article 86 permission.
The CAA will prosecute - trust me on this. They simply need proof of what went on or advance warning that an event like this is happening.
Regardless - in the event this idiot did crash, the CAA would be notified (and the AAIB on certain occasions) and the helicopter hull insurance would be null and void. IF their TP insurance was insufficent to pay off damages, the pilot first and then the owner or company 2nd would be pursued for damages. This normally has the effect of bankrupting some or all of the stakeholders in the helicopter.
[This is often referred to in insurance as - "an extinction event"].
EU 785/2004 legal insurance cover is often always insufficient to cover modern day damages.
Looking at the video. I can GUARANTEE that he was never allowed to close the crowd to less than 75m (exemption), nor would he EVER be allowed to overfly the spectators or the house.
Over to you.....................