I just found a story in The Motor Cycle’s Olympia Show preview, 1913:
“The Craven Motor Co., 116, Greenwood Road, Dalston Lane, N.E., market
a sidecar combination possessing’ several novel features, the chief being the manner in which the rear wheel of the 9 h.p. J.A.P.-engined machine is sprung on leaf springs. This naturally gives great resiliency, and the wheel cannot shift, as it is in a rigid frame, the springs being placed above the rigid forks and the rider’s weight corning on another frame which is placed on the springs. The sidecar is also sprung on similar type springs, to the ends of which the body is secured by bolts passing through the floor. On the roughest roads little shock can reach the driver.”
There’s a pic of a two-seat Craven wickerwork sidecar later the same year but nothing the following year so it looks like it didn’t get into full production. Judging by the pic that might be a good thing.