I think it was a TV show, but it could be a movie. I watch it somewhere in early or mid ‘90s but it could be from ‘80s. I think it was British.

There was a girl who lived in big manor. There was a garden in front of the manor and there was a sundial on that garden. And there was a boy, who (I think) always show up at the same time of a day. The girl thought he was a ghost. One day they talked next to the sundial and he offered her his hand. Because she thought he’s a ghost, she hesitate, but as I remember he was not a ghost so her hand didn’t go through his hand. This is all what I remember.