Fine day to get into repeat of Love Island (4-5)
I believe the answer is:
okey-dokey
'fine' is the definition.
(I've seen this before)
'day to get into repeat of love island' is the wordplay.
'day' becomes 'd' (abbreviation for day).
'to get into' is an insertion indicator.
'repeat of' shows that letters should be duplicated (I've seen 'repeating' mean this).
'love' becomes 'o' (love means zero in tennis).
'island' becomes 'key' (key can mean an island or reef).
'o'+'key'='okey'
'okey' duplicated is 'okeyokey'.
'd' put into 'okeyokey' is 'OKEY-DOKEY'.
(Other definitions for okey-dokey that I've seen before include "I agree - it's fine!" , "Version of OK" , "All right (informal)" .)