What isnrhe sound I am hearing at night?

I have lived in quite a few places, am not unfamiliar with outside noises. Sure, the birds are annoying at 4.30am. One place I lived right by a railway with construction going on all night.

But where I live now, I hear a few drunks going past, seagulls in the morning. I can drown it out. Except for 'BEEP! Beep beep beep.... BEEP, beep beep beep' and it is all night. I'm living in a house, nothing sounds like that inside. It is only when I am outside having a cigarette or when I am in my bedroom trying to sleep with the window open. What the hell keeps going BEEP, beep beep beep...BEEP beep beep beep? All night?

Does anyone have any ideas before I go off on my neighbours? My mum has stayed for the last week, she cannot hear it so maybe some cat deterrent device. My sister has been over to visit and she heard it too.

I have spoken VERY LOUDLY about it tonight with my mum whilst we were in the back garden, so maybe the culprit will stop it without driving me too crazy.

Just curious if anyone has any idea what does that all night?