To find out which buses run from one place to another use traveline.info. This site also tells you when they run and which particular bus stop you need.
This bus company running the local 21 service doesn't have a website (how very retro). The franchise switched operators recently and either the new operator is SM Coaches or the new operator bought vehicles from the previous operator who was SM Coaches.
I turned up at the bus stop early so I wouldn't miss the bus. Right on cue a number 71 approached. I hesitated. From a distance a seven can look like a two without a bottom. I let it pass.
I waited. My bus was late.
I looked around the bus stop for clues that my internet research was correct. There was nothing. No timetable or any kind of bus information. It could just as easily be a resting place for a weary as it could be a bus stop, apart from the sign that said "bus stop".
Six minutes late, my bus arrived. And I found a new way to get from my house to Ongar.
One of the reasons for taking the bus was to check the route worked, and it does. And I had a little adventure along the way.