This was actually on TV when I was a kid. I wanna’ say on PBS or something like that. I remember it being on along the same time as Rocky and Bullwinkle was. Early in the mornings (for me on the east coast, US) like 4-5:00 before the other channels started their cartoon runs. I slept weird when I was a kid so it was either the first, or last thing I saw during the day.
I remember being a confused little kid when they said he lived in a pillbox, when it looked like a mailbox. I guess pillar box is British for mailbox. :)