We live in a quiet cul de sac and we are on nodding or chatting terms with nearly all the neighbours.....but the man who lives at the bottom...4 doors from us, is reserved and never says hello unless you REALLY look him in the eye and he cant avoid it....fair enough....but......my DC are 7 and 3 and the 7 year old goes out the front which is all open plan and rides her bike a lot....I usually keep an eye on her from the kitchen window
Whenever she does, he appears at the front of his property and messes about with something....he loiters iyswim.
Hes never actually DOING anything, just now he was sort of pushing his bin around...repeatedly re-positioning it.
My 3 year old wanted to go out so DH went with her and thats when he saw the neighbour kind of peering at our older DD from the cover of his garage...he was JUST inside and half hidden. 
I cant see his house from my window as it's on my side....
AIBU to ask the police for one of those disclusure things?
This man lives alone and is about 55. He seems "normal" if shy/anti social.
WWYD?