Nameless Movie??

[tre00]

Hopefully someone out there in the TCM universe can help. Im trying to find a movie, but I for the life of me, can not remember what the title of the movie is. I remember parts of the movie and so maybe that may help.

The movie is a supernatural/ghost/mystery movie. It looks as it as been made between 1960-1981 and its a period piece set in england. It involves 2-3 kids who move into a cottage/mansion (a big house). They meet an old man there who i think is the caretaker. After staying there for a bit, they meet up with a boy and somehow they end up taking a potion that takes them back in time to the ppl who lived in the house. THe reason for going back in time I cant recall exactly, but it involved investigating something that had happened already in the house. while back, they made some discoveries. the caretaker who cares for the children is a part of the household in the past too. and a raging fire breaks out and the caretaker tries to save someone, but is actually caught in the flames. the children make it barely back to their time and see that the caretaker is actually a ghost.

Thats all I remember. hopefully it helps. can someone please help me>?