RP,
I have pointed out before most of the time UK police ASU money and manpower is wasted on mundane petty crime such as this incident.
In your first example, what if known associates of the arrested man in the van were wanted murderers?
In your second example, how can you possibly know the previous history of that address and more specifically what happened that particular evening. If you read your post, the helicopter was looking for a vehicle. Just because no arrests were made, doesn't mean there was no baddy to arrest (Carl Mills ring any bells?)
There's always a bigger picture my friend, personally I have seen your so called mundane and small incidents turn into some quite large ones.
Please define for us 'mundane petty crime' and 'small incident' .