Probably the most well known Brox Compact in the UK, Firebrox is the main sound system for the London Friday Night Skate.
I caught up with it at the original 2007 London Freewheel. Note the striking blue wheel hubs.
The machine is heavilly modified to help carry the 2kW PA system, with 52 gears and from odd forum posts it seems the hard work it goes through results in it needing a significant amount of maintenance, there is a detailed post covering the problems here.
Thanks to dan_b's comments and his photos on Flickr (below) I can now tell the correct series of events. The version of Firebox in my photo above, piloted by dan_b, was bought as chassis plus the aluminium flatbed load tray in 2006 from an employee of Brixton Cycles.
There were two versions of Firebox, the first was based on the standard tray (plus a repaint) and a steel support for the speaker:
And the second has the reworked back,
dan-b also sais that "Sadly it's currently off the road *again* as the drive axle snapped earlier this year and we've been unable to source a replacement. We're planning to take it down to Kingsmead to get the rear frame rewelded: I'm told that their newer design uses a plain axle instead of the complicated piece of machinery in ours, and they can fit mountings for Magura brakes at the same time."