The bike is an LMC of about 1911, built by the Lloyd Motor Engineeering Co., one of W.J. Lloyd's ventures. The pivotted bottom link fork is an LMC feature (although I think it may have been made by Chater Lea), as is the dual brake shoe arrangement on the belt rim. I'm not sure what the gear/free-engine device is, but it looks to be one of the ones that spreads the flanges of the front pulley against spring pressure. You get a bit of a gearing effect with devices like this, but not much because the belt loosens as the gear is reduced. There is often a free-running ring at the bottom of the pulley groove, so that with the flanges wide apart the belt sits on the ring and does not drive. A form of clutch, but pretty hard on the belt at take off.
The story goes that many/most LMCs were exported to the colonies. This may be true: they are not particulalrly rare out here in Australia.
Leon