Peter Firmin intended Bagpuss to be a striped marmalade (orange) cat but the company who wove the striped furry cloth had a manufacturing fault and used pink thread instead of orange. This is the origin of Bagpuss the pink striped cat.
The "shop" featured in Bagpuss was in reality the rear of Peter Firmin's house. He decided it looked appropriate for the series and cast his daughter Emily as the girl in the monochrome introduction.
The first 2 minutes 51 seconds of each program is identical. This is an unusually long time, but did set the scene for new viewers. And of course children love repetition.
Professor Yaffle was the most complicated puppet and the most agile being the only one with moving legs and feet. To keep him upright during filming his feet had to be tacked to the surface. The tacks can be seen appearing and disappearing in various combinations in the four small holes in each foot, depending on what position he was adopting.