The suspension of a person under the aircraft on a rope would need a specific CAA permission in any case; it's not something to be attempted just because someone asks. Knowing the CAA stance on singles, I doubt it would be allowed in any planned circumstances.
There was a certain pilot who was prosecuted by the CAA because someone accidentally became entangled in the USL gear after load pick up. First thing the pilot knew about it was when the same "hooker up" appeared underneath the helicopter at the drop site, unhooking the underslung load.