Start scrubbing away, there's a good chap (5)
I believe the answer is:
'a good chap' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe there's an association between them I don't understand?
'start scrubbing away' is the wordplay.
'start scrubbing' becomes 'sc' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'away' becomes 'out' (similar in meaning).
'sc'+'out'='SCOUT'
'there's' acts as a link.
Can you help me to learn more?
(Other definitions for scout that I've seen before include "Lookout or pathfinder" , "Soldier on a recce mission" , "Member of a youth movement" , "One making recce" , "Person sent out to gain information" .)