Coff, the transponder is the Becker remote head in the image
see
BECKER SCS-150 REMOTE COM/TRANSPONDER MODE S PACKAGE from Aircraft Spruce Europe
As they are using the Becker set up I would say they are probably using their altitude encoder module that is simply plumbed into the static system , see
http://www.becker-avionics.com/downl...nstruction.pdf
I think you will find Flarm is being fitted throughout the BBMF fleet.