you are correct about the swinging arms being 19" and it is a well known measurement as it is one of the main differences between Cromwell and cavalier, the crusader (Cromwell was designed as a requirement for a heavy crusader) also had 19" arms but these were changed to 15" on cavalier then back to 19" on Cromwell.
like Adrian pointed out there are no torsion bars although the mountings on the hull floor look like they could be torsion bars. the suspension uses coil springs and dampers. the housings on the hull floor hold the bearings and swinging arm shaft, interestingly the shaft bearings are auto lubed by a pipe system which lets a drop of oil onto the bearings every time the clutch pedal is engaged, bit of Cromwell trivia :-D