August bicycles was selling a widget to do this with Thompson seat clamps
https://www.augustbicycles.cc/online-store/Light-bracket-barrel-nut-to-suit-Thomson-Seatclamp-and-Supernova-E3-tail-lamp-p245693406
Neat. Need to make up something similar to work with the B+M.
@jameso started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
August bicycles was selling a widget to do this with Thompson seat clamps
https://www.augustbicycles.cc/online-store/Light-bracket-barrel-nut-to-suit-Thomson-Seatclamp-and-Supernova-E3-tail-lamp-p245693406