The first example is the use of a Smart & Brown A-4 (In-Line) hub, plus control lever and wire, in conjunction with a non-TriVelox gear mechanism, possibly a Huret, the latter simply providing tension to the chain. They are fitted to a B.S.A. tandem that belonged to Garry Barker who, as a very impressive side-line, builds replica Dursley Pedersen frames, an example of which is also shown.
The second example is the use of a Smart & Brown off-line gear mechanism and its controls - the B and C models used the same mechanism - in conjunction with a Bayliss-Wiley unit hub, effectively creating a B-type model. They are fitted to a solo Sunbeam Silver Sports belonging to Bob Damper, a member of the Veteran-Cycle Club. Information on the Bayliss-Wiley unit hub can be found here.