Blimey! Half full in Greek island? (5)
I believe the answer is:
corfu
'greek island?' is the definition.
(I've seen this before)
'blimey half full' is the wordplay.
'blimey' becomes 'cor' (I've seen this in other clues).
'half' indicates taking half.
'full' cut in half is 'fu'.
'cor'+'fu'='CORFU'
'in' acts as a link.
(Other definitions for corfu that I've seen before include "Major holiday island off west coast of Greece" , "Greek island, a British protectorate in C 19" , "Largest of the Ionian Islands" , "Kerkira, Ionian island" , "Island off west of Greece, popular for holidays" .)