here I found this for you of another site not half as good as riu but anywayS: I asked a UK copper staight-up if they look for grow ops in the UK with IR and he said flat-out "No"
He is a well trusted (known him over 20 years) source and says the chopper is so busy on requests that they don't do that sort of thing. Human intelligence (humint) is still the no1 lead they get for busting grow-ops. He's busted a fair few too so he really does know what he's on about.
Obviously this is in one part of the UK - but you can imagine that other Police forces around the UK are the same. The helicopter costs a staggering amount of money to keep airborne and it is constantly responding to officer requests for support.
However.....
I think a whole row of houses with all the loft areas of the houses running grows in them - that would get spotted if the chopper crew bothered to point their IR equipment at it. They are usually pretty busy though - which is good news for us.
He did ask me afterwards if all the weed I was smoking was making me paranoid - lol you gotta laugh, its a fucked up world.