Owain wrote:

Something like a pressure washer drain cleaning end, but with
compressed air instead of water?

Feasible! Blow the lot out of the top too, so no soot coming downwards!

Radio-controlled model helicopter with brushes on the rotor end, and
CCTV camera so you can see where it's going?

Long-haired cat, hairspray it so the fur forms bristles.?

Bass guitar amp in the fireplace pointing upward, and vibrate the soot
off.

Very amusing! LOL.

Eddy.