Monicker of English chap, taken up following prison (8)
I believe the answer is:
nickname
'monicker' is the definition.
(I know that monicker can be written as nickname)
'english chap taken up following prison' is the wordplay.
'english chap' becomes 'eman' (I can't explain this - if you can you should give a lot more credence to this answer).
'taken up' says the letters should be written backwards.
'following' is a charade indicator (letters next to each other).
'prison' becomes 'nick' (slang term for prison).
'eman' in reverse letter order is 'name'.
'name' after 'nick' is 'NICKNAME'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for nickname that I've seen before include "Agnomen" , "Familiar appellation" , "Familiar moniker" , "Familiar form of address" , "term for someone" .)