Restaurant sent back article on large vessel (7)
I believe the answer is:
taverna
'restaurant' is the definition.
(I've seen this before)
'sent back article on large vessel' is the wordplay.
'sent back' says the letters should be written in reverse.
'article' becomes 'an' (indefinite article).
'on' becomes 're' (regarding).
'large vessel' becomes 'vat' (I've seen this in another clue).
'an'+'re'+'vat'='anrevat'
'anrevat' in reverse letter order is 'TAVERNA'.
(Other definitions for taverna that I've seen before include "Greek guesthouse" , "Greek inn" , "Greek bar/restaurant" , "Small Greek restaurant with bar" , "pub" .)