Graham were motorcycles produced from 1903 to 1904, in Enfield, which is now part of Greater London.

At the late-1903 Stanley Show, the company exhibited their flexible sidecar attachment. One was fitted to a Humber and the other to their own machine, powered by a De Dion engine.

Graham Bros.

This firm, which was amongst the pioneers in the designing and construction of the motor sidecarriage, will be exhibiting one of its patented sidecar attachments fitted with upholstered basketwork, well hung on double Cee springs, fitted with motor tyres, plated rims, and side mudguards.

The Motor Cycle, November 18th, 1903. p801
Stanley Show 1903

1903 Stanley Show

Graham Bros.,
Enfield Town, have on their stand two models of their flexible sidecar passenger attachment, in the one case fitted to a Humber chain-driven motor bicycle, and in the othér fitted to a motor bicycle of their own make, fitted with a De Dion engine and a Longuemare carburetter. (Stand 182.)

The Motor Cycle, Nov 25th 1903

Sources: Graces Guide, The Motor Cycle.