Is their bathroom/toilet likely to be above your door?
Had the same problem in my house - was the overflow from my toilet (non close-coupled)
The ballcock in the cistern was old and sticking on it's way back up and not returning to the fully up position and the water would keep trickling out...
My hot water pressure has a slight problem (combi boiler)
You turn on the hot water (in the sink say) and the flow is fine and the combi kicks in, but then after a few seconds, the flow decreases rapidly, the water goes all cloudy until eventually the combi goes off.
You increase the flow...