There is only one known silhouette recorded by J.C Garside. Jackson (Dictionary) gives the date as 1830, and describes in detail a portrait of Lieutenant-Colonel William Everett. Unfortunately, this is the only information currently known about this silhouette artist.
Source: McKechnie (Author of, British Silhouette Artists and their Work 1760-1860)
Garside, J. C. (McKechnie Section 2)