I find that a polite "Excuse me" often ilicits a "Haven't you got a friggin bell"? type of response.
I've had that sort of thing.
Even on a shared path where I was quite happy to cycle at walking speed until the path was wide enough to pass safely. The pedestrians ahead suddenly noticed I was behind, at about 3 bike lengths back, and one shouted "Use your bleeding bell!
"
A cyclist thing that happens occasionally and bugs me a little on group 'pootle' rides.
Recently Arch and I were on a cycle route, just about wide enough for two abreast cycling, with some friends and I was riding sometimes adjacent to Arch talking to her or just behind her chatting away. One of the cyclist would 'sneak' up and ride just level with my rear wheel, out of my sight unless I look over my shoulder, not passing, not leaving me any wobble room, not talking, just slowly squeezing me towards the edge of the path.
Why? Either ride behind, ride level, or pass, or at least say something so I know you are there rather then sneaking up and making me jump and then riding into my space.