Green’s Dictionary of Slang

sheepie n.

[abbr. + sfx -ie]

a sheepskin coat or jacket.

[UK]K. Sampson Awaydays 3: One or two of the older lads have still got Bee-Gee centre-parts and sheepies.
[UK]K. Sampson Outlaws (ms.) 92: He used to look like Bob Carolgees, years ago when he had a bad muzzy and a sheepie.