Run round balloon: UFO crashed here (7)
I believe the answer is:
roswell
'ufo crashed here' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'run round balloon' is the wordplay.
'run' becomes 'r' (cricket abbreviation).
'round' becomes 'o' (round can mean a round object).
'balloon' becomes 'swell' (I've seen this before).
'r'+'o'+'swell'='ROSWELL'
Can you help me to learn more?
(Other definitions for roswell that I've seen before include "New Mexico city" , "town in New Mexico" .)