What exactly is it you are wanting to know? Do you have him in census records or do you want to move back with his parents?
I took a quick look in the 1841 census using the spelling Steel and there were three in Devon. The one closest to a 1820 birth was born c1811 and was residing Saint Mary Street, East Stonehouse.
He was with his wife Mary 30 and children Susan 5, Elizabeth 2.
Thomas and Mary not born in County, both children were.
Thomas was in the Army, no other info.
Bracketed in with Thomas' household is an Elizabeth Sinclair, 30, Dressmaker, not born in county.
Scrap this one. See later post.