Warning from Spooner in the kitchen, where there’s great activity (7)
I believe the answer is:
hotspot
'warning from spooner in the kitchen' is the definition.
The definition suggests a singular noun which matches the answer.
'there's great activity' is the wordplay.
'there's great' becomes 'hot' (I can't explain this - if you can you should give a lot more credence to this answer).
'activity' becomes 'spot' (spot is a kind of activity).
'hot'+'spot'='HOTSPOT'
'where' acts as a link.
Can you help me to learn more?
(Other definitions for hotspot that I've seen before include "Nightclub" , "busy area" .)