Bloc on reflection regret Australia joined (8)
I believe the answer is:
eurozone
'bloc' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'reflection regret australia joined' is the wordplay.
'reflection' says the letters should be written in reverse.
'regret' becomes 'rue' (to rue something is to regret it).
'australia' becomes 'oz' (informal name for Australia).
'joined' becomes 'one' (I've seen this in another clue).
'rue' back-to-front is 'eur'.
'eur'+'oz'+'one'='EUROZONE'
'on' is the link.
Can you help me to learn more?
(Other definitions for eurozone that I've seen before include "Group of countries using a common currency" , "Continental currency area" .)