Here's what I don't understand:
I was on the first ever flight to land at LCY - before it got licensed. At that stage the planning requirement forbade anything other than prop fixed wing. Within a few years of opening, EGLC was accepting "whispering" jets - proving that planning is moveable.
But you still can't land a heli there - even if you're the Met. (Although Dennis Kenyon was allowed in during one Saturday "closed" period to do a display - but that was at the annual City community air day.)
The management of EGLC were recently quoted as saying they would like to manage a new heliport for London somewhere near their field, but not ON their field.
Why not ? They are about to accept Airbus FW - which must be noisier than most light helis. So why not create a "light" heliport at City for nothing bigger than Group 3 helis ? A perfect hub integrating with the scheduled fixed wing services. There's plenty of space........