Some haven to which no-one returns (7)
I believe the answer is:
portion
'some haven' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'which no-one returns' is the wordplay.
'which' becomes 'port' (I am not sure about this - if you are sure you should believe this answer much more).
'one' becomes 'i' (Roman numeral).
'returns' is a reversal indicator.
'no'+'i'='noi'
'noi' written backwards gives 'ion'.
'port'+'ion'='PORTION'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for portion that I've seen before include "Segment" , "Serving" , "Part - share" , "Part of a whole" , "A lot of" .)