XX: I don't think any of us here work for CAA SRG. They are the ones who can answer your questions with authority (unless they say "get your own legal advice" which is the standard answer to any question which threatens their pension...)
Your state of mind worries me. "Very unlikely to crash" isn't an expression I've ever encountered with regard to permissions/exemptions. Are you sure you took Aviation Law in your PPL ?
You must read Rule 5 before you even attempt to ask for a CAA Exemption. So get
CAP 393 in pdf form and search for rule 5. And do some searches for Exemptions.
You seem to have shifted your interest in landing sites from helicopter to Jodel FW. Different kettle of fish. FW treated differently in our only Class A space. Helicopters derive great benefit from NATS-issued Non Standard Flight permissions. Since a Cessna single overflew the West End towing a banner a few Christmases ago I believe the answer to FW singles asking for an NSF over a lot of London is no.