The Starlings on Shetland are generally treated as a subspecies, zetlandicus. BWP tells us that they are intermediate in size between faroensis and nominate vulgaris, with a slightly wider bill at base than nominate but similar wing length. The most striking difference is that juveniles are sooty brown, with little white on the chin and belly and bold black spots on the white throat.
Here are two from Toab, where they have appeared during the last few days: one which has just left the nest cavity, and one slightly older. Note how light affects the apparent shade of the plumage.