Deduce the fire had spread round about mid-evening (5)
I believe the answer is:
infer
'deduce the fire' is the definition.
'infer' can be an answer for 'deduce' (synonyms). I'm unsure of the 'the fire' bit.
'spread round about mid-evening' is the wordplay.
'spread round' becomes 'fer' (I can't justify this - if you can you should believe this answer much more).
'about' means one lot of letters go next to another.
'mid' indicates the central letters.
'evening' becomes 'becoming even' ('become even' can be a synonym of 'even').
The middle of 'becomingeven' is 'in'.
'fer' after 'in' is 'INFER'.
'had' is the link.
Can you help me to learn more?
(Other definitions for infer that I've seen before include "Draw meaning from" , "come to a conclusion" , "Work out" , "Extrapolate, conclude" , "Read between the line" .)