The fire damage around the hole in the soffit. The feeder had been chafing on the edge of the hole for years.
Bullet connectors had been arcing. So the lesson is to stagger them along the feeder by a few inches and cover exposed wire with heat shrink tubing.
Pretty cool that I can work stations around the world with an open-circuit feeder.
The fire had melted and consumed 0.5m of flammable insulation.
Inside the loft space molten insulation had fallen on this spare coax that the feeder was taped to.