Ok so around quarter past nine I'm coming back from the local shop ( essential gin run) the quickest route is the alley behind my house. There's plenty of lights plus most people have garages or drives there instead of on their respective roads so it's more like an unnamed road than an alley. There's a man walking his very small dog up the road. It enters my road at an angle. He basically walked up the alley and then walked back a fair distance back to the road he came from. I was 20 ft behind him. It was still daylight. He kept swerving from one side of the alley to the other and sticking his head over random people's back gates. Including my friends 12 doors up froom mine. Even though the dog was usually pulling in the opposite direction. he got to mine (which is due to being an end terrace have a huge garden footprint) and he looked over 6 times. I caught up to him and recognised him as the local scrap man I had a brand new bike in the garden that i'd left out as only my ex can open the gate on the outhouse. Every time he looked over he was focusing on it. I put it straight into the outhouse with my ex's help but I'm still worried not just for my bike safety but for anything else he was eyeing up in the alley. When he realised I was behind him he attempted to appear drunk to excuse his peering into random gardens but I'd watched him for a good 10 mins before he realised I was behind him. We've had a spat of 'scrap men robberies'in the area. Really don't know if I'm over reacting or not at this point. (Also I know said scrap man doesn't live nearby so it's really unnatural to see him walking a dog he clearly doesn't know)