Demon Headmaster was ACE!
I remember loaRAB of old progs but stand-out ones include:
Century Falls with Simon something or other, Fenton, that's it! Who was also in Kriss Kross, a boarding school setting with a cool black american kid befriending a white posh goody-goody (Fenton). Century Falls was about a creepy village where all the villagers worshipped some weird god thing... was written by Russell T. Davies no less.
As was Dark Season, about a school that got hypnotized by computers given by a mysterious benefactor called Mr Eldridge, turned out they needed a blonde virgin to sacrifice to the Behemoth, a massive intelligence force thing that was going to take over the world... really scary stuff! Had Kate Winslet in it and was also written by Russell T.
These were both around 1990/1991 I think.
Byker Grove was bloody brilliant too when I was a nipper, Gill, Donna, Nicola, Winston, Spuggie, PJ and Duncan, Debbie etc. Then it went a bit sh*t. I still remember Gill crashing his car in to that lorry and Winston shouting "Giiiiiiiilllllll!!!!!". Then Julie was preggers! I was waaaay too young to be watching that - about 8/9 I think??
All good stuff!