The sound you describe i'm none to sure about, but the sticking/juddering could be a caliper sticking or a rear drum if you have drums at the back, when did you last have the brakes serviced properly, and i don't mean someone peering at them or squirting brake cleaner at them.

If I understand corectly, problems apear only when you move the car.
My opinion is that you need new brake pads, old ones may have split from friction material. This usualy happens when rust starts forming between brake material and metal plate.
If you don't use the car often enough and end up changing brake pads as often as once every 5 years , I recomend painting pads with heat resistant paint so they can be protected from watter, salt or other contaminants that you might get from road use. Use heat resistant paint where friction material joins metal plate. Clean brake pads before you paint and don't spray brake cleaner directly on them as friction material might react and "swell"

If hising sound apears on engine startup, you may have vacuum leaks.