[TOMT][MOVIE][70s/early 80s] Psychic/Ghost kid story but other dimension?

There was this weird show that would do the round when oddly Disney classics. It was about this woman who lost her daughter but was haunted by her? Only she wasn't really missing, but trapped in another dimension?

There was more kids (especially a girl around the same age?) who could sense the missing girl. There was some ghost-like being who caused the problem. It was dark and had that late 70s/early 80s style movie production. Very much Escape to Witch Mountain but if it was set in England or the Northeast America vibe to it.

Eventually the new girl and others contact and 'save' the lost girl who hasn't aged a day, even though her mother is much older.

What is this movie?!