To his credit, he took an order conscientiously (8)

I believe the answer is:
cromwell
'to his credit he took an order conscientiously' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'to his credit he took an order' is the wordplay.
I cannot quite understand how this works, but
'credit' could be 'cr' (abbreviation) and 'cr' is found within the answer.
'order' could be 'om' (Order of Merit) and 'om' is found within the answer.
The remaining letters 'well' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for cromwell that I've seen before include "dictator" , "He gave the Irish the choice of going ''to hell or to Connacht''" , "Leader of the Roundheads, d.1658" , "Oliver, Puritan leader during 17th century English Civil War" , "Old English statesman" .)
