British artists hold very posh show of brilliance (7)
I believe the answer is:
bravura
'of brilliance' is the definition.
'bravura' can be an answer for 'brilliance' (I have seen 'Great brilliance ' mean 'bravura' so perhaps 'brilliance' could also mean 'bravura'). I'm unsure of the 'of' bit.
'british artists hold very posh' is the wordplay.
'british' becomes 'br' (abbreviation for British).
'artists' becomes 'ara' (I can't explain this - if you can you should give a lot more credence to this answer).
'hold' is an insertion indicator.
'very' becomes 'v' (abbreviation).
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-U).
'v'+'u'='vu'
'ara' going around 'vu' is 'avura'.
'br'+'avura'='BRAVURA'
'show' acts as a link.
Can you help me to learn more?
(Other definitions for bravura that I've seen before include "Display of boldness" , "Audacity" , "Brilliance - dash" , "Virtuoso music" , "Spirit and dash in music" .)