Official YouTube Channel
From The Lost Media Wiki
I don't know too much about the series but looks like the official Mr Men YouTube channel has been uploading the original 1970s-80s series in high quality. Little Miss: https://www.youtube.com/watch?v=ZkDJpiPwDH4&list=PLEE_AAyHzperCMBl2PARxOzAk-GxIXl8t&index=1 Mr Men: https://www.youtube.com/playlist?list=PLEE_AAyHzpepnqciAyvUwtKrLav5NMXwu