My friend is a copper in Leeds and they use them - she said it was likely to be looking for heat sensors if they hover over head for ages - if they were flying to hospital why would they keen hovering? Also my flat mates uncle rented a house out - and found out via the police and a heat sensor helicopter that it was being used to grow cannabis plants - millions of them - in the attic, and all the bedrooms - downstairs looked totally normal - upstairs massive cannabis farm. I am not saying that is what these helicopters are - it was just what i had been told.