As is the nature of these things, the buzzy noises from the bottom of the windscreen/shield came back! (They were triggered by temperature and certain road surfaces).
This time I have sprayed the area with "non-fling motorcycle chain lubricant", using the aerosol with a couple of feet of quarter-inch plastic tubing on it to direct the grease jet right to where I want it, down the slot.
This method worked, and is still working, on the suspension rattles from the rear of the car. In six months or so, these suspension rattles haven't come back. Thusly saving me a lotta dosh.
"Rattles, rattles go away, don't come back another day".
Leedsman.

 

Ingenious solution Leedsman. No caustic greasy smell from the lube I hope?

 

I've got to say, my XJ8 with 222,000 km on it, sails down the road in silence, not a squeak or rattle to be heard, while my wife's X5 with 160,000 km creaks groans and rattles like crazy!
I don't drive the X5 unless I have to now.

 

No nasty 'niffs from the product I used!
But after many rattle battles, I know the gremlins aren't gone until they're gone well and truly....
Leedsman.