Spiv's moment to worry? (5,5)
I believe the answer is:
flash harry
'spiv's' is the definition.
(I've seen this before)
'moment to worry?' is the wordplay.
'moment' becomes 'flash' (I've seen this before).
'to worry?' becomes 'harry' (I am not sure about this - if you are sure you should believe this answer much more).
'flash'+'harry'='FLASH HARRY'
Can you help me to learn more?
(Other definitions for flash harry that I've seen before include "Show-off" , "wide boy" , "one likes to show off" , "Vulgar type" , "Spiv" .)