Designer good one around posh clubs twice (5)
I believe the answer is:
gucci
'designer' is the definition.
(I've seen this before)
'good one around posh clubs twice' is the wordplay.
'good one' becomes 'gi' (I am not sure about this - if you are sure you should believe this answer much more).
'around' indicates putting letters inside.
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-U).
'clubs' becomes 'c' (abbreviation used in card games such as bridge).
'twice' indicates the doubling of some letters.
'c' duplicated is 'cc'.
'u'+'cc'='ucc'
'gi' going around 'ucc' is 'GUCCI'.
Can you help me to learn more?
(Other definitions for gucci that I've seen before include "Italian fashion house" , "Italian designer" .)