Group stealing jewel and cheap regalia finally unlocked crown? (4,5)
I believe the answer is:
bald patch
'unlocked crown?' is the definition.
(area with no hair or locks)
'group stealing jewel and cheap regalia finally' is the wordplay.
'group' becomes 'batch' (a batch is a group or set).
'stealing' means one lot of letters goes inside another.
'finally' suggests the final letters.
The final letters of 'jewel and cheap regalia' are 'ldpa'.
'batch' enclosing 'ldpa' is 'BALD PATCH'.
(Other definitions for bald patch that I've seen before include "Hairless area" , "Place where hair has been lost" , "sign of ageing" .)