I'm afraid I don't know anything about Charles' army record, but maybe there's some info on what the Sherwood Foresters were doing at
www.wfrmuseum.org.ukI've had a bit of a look at some records and have found an 1841 census record for Isaac, b. abt 1811 (but bear in mind that adults ages were rounded on that census) living in [what looks like] Rivett Street, Derby. He's a "porter" living with
Elizabeth, age 31, not born in Derbyshire
Sarah, 5, born Derbyshire
Hannah, 3, born Derbyshire
John, 10mths, born Derbyshire
Isaac, 79, not born in Derbyshire
and
Martha, 32, born Derbyshire, silk winder
[I'm thinking that Martha and Isaac - the head of the household one - are brother and sister]
I also found him on the 1871 census, which shows him as being born abt 1808.
Do you have a marriage for Isaac and Elizabeth, or any other info?
STG
Edited to say : IGI has a marriage on 26 Feb 1833 at St Peter's, Derby (same parish they're living in in 1841) between an Isaac Wilkinson and an Elizabeh ARCHER.