Go to Scotland, leaving our radical group (4,2,4)
I believe the answer is:
gang of four
'radical group' is the definition.
The definition suggests a singular noun which matches the answer.
'go to scotland leaving our' is the wordplay.
'go to scotland' becomes 'gang' (I've seen this before).
'leaving' becomes 'off' ('I'm off' means 'I'm leaving').
'gang'+'off'+'our'='GANG OF FOUR'
Can you help me to learn more?
(Other definitions for gang of four that I've seen before include "Chairman's advisers" , "political faction" .)