The fellow Mr. Bloggs left behind (4)
I believe the answer is:
joel
'the fellow mr' is the definition.
'Joel' can be an answer for 'mr'. I am not sure about the 'the fellow' bit.
'bloggs left behind' is the wordplay.
'bloggs' becomes 'joe' (I can't justify this - if you can you should give a lot more credence to this answer).
'left' becomes 'L' (common abbreviation).
'behind' is a charade indicator (letters next to each other).
'joe'+'l'='JOEL'
Can you help me to learn more?
(Other definitions for joel that I've seen before include "Old Testament prophet" , "Book of minor prophet" , "book in church" .)