The wires for the rear brake light are under the seat and luckily, there is a connector there too to make it more obvious which one it is.
All done, I chose to solder mine as I don't like the snap-on and crimp connectors supplied. The SBM has to be mounted flat, so I relocated the alarm connector (triumph protect+) which is unused on mine, to allow the SBM to have a nice flat mounting with some velcro
edit: p.s. have since cleaned that area, the photo's show a lot of sand and muck... it's all gone now