I remember being shown a series at school (about 17–19 years ago) and I really enjoyed it however all I can remember is:
There was a young lad and girl who had some kind of portal in a box which if I remember right looked like a house but with 2 pillars on the front. Then the doorway became the portal. Towards the end of the series the portal was massive and something was threatening to come though it.
I know it’s not much to go on, but it’s really annoying me now.
It was a series and I think it was shown on BBC (it was definitely shown in England, and in English).