There was a creepy programme we watched when I was at primary school, possibly about a haunted house. The main characters were children. This would have been early 1980s in the UK. We watched it at school for some reason, then it must have been repeated as I saw it again on TV on holiday. It left a strong emotional impression but I've never worked out how to find out what it was.
The one thing I do remember is someone at school pointing out that the character names started A, B, C (e.g. Alan, Betty, Claire). These characters were probably the children.
It was definitely live action as I've a vague memory of seeing child actors. I remember finding it creepy, so I'm pretty sure there was something fantastical/supernatural about it. My emotional memory of it is a bit like watching The Twilight Zone (albeit one for eight year olds!), where there's a weird, unusual concept, which caught my attention.