Unwanted delivery of boat, man reported (4,4)
I believe the answer is:
junk mail
'unwanted delivery' is the definition.
'boat man reported' is the wordplay.
'boat' becomes 'junk' (type of Asian ship).
'man' becomes 'm'.
'reported' becomes 'ail' (I can't justify this - if you can you should believe this answer much more).
'junk'+'m'+'ail'='JUNK MAIL'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for junk mail that I've seen before include "Unsolicited post, such as advertising etc" , "Unwanted post" , "Circulars etc" , "post to ditch" , "Unwanted letters" .)