Thank you Suz.
Really interesting site, well worth a look.
Have been to Derby RO and found 'Calendar of Prisoners' (thank you to the RO staff) with details of the General Quarter Sessions at Derby.
Details were Name/Offence/Judgement
Fascinating to handle documents from 1868 - lots of names, I was able to confirm my link via 1871 Census which gave details of place of birth. Didn't look at them all and happened to pick the right one straight away

Mine was tried for "Larceny & Possession" which was the most common offence and got 3 years
Knellie