Aleš Lombergar

Yes. I got them imported from Australia on video cos I used to love this a few months back. It was called Finder’s Keepers and was about a kid called Patrick (played by Jeremy Schwerdt) who was invited to be a contest on a game show called Finder’s Keepers across the barrier. Patrick had to be at the shopping centre at the same time each week at the same television set with his find. Each time Patrick crossed the barrier it was having an effect on him. Also his babysitter Estelle was from the other side and she was trapped, fading away. She had the final find, which was a ring and she wouldn’t give it up so Patrick took her back with him which caused the barrier to go haywire and the robot presenter Lucky to shut down. The people in orange overalls were barrier guards who looked after it by throwing things back to the other side if they got lost, for example keys and socks.
The show was based on the books by Emily Rodda which I have also.
Hope this helps and to answer your your last question, yes I do remember this

is it Finders Keepers? also called The Finder

The story revolves around a boy by the name of a Patrick who, whilst playing on his computer, receives an invitation to take part on a TV game show called “Finders Keepers”. He accepts the invitation and is sucked into another world where he is given clues to find missing treasures from his own world and take part in a time travel hunt.

Does anyone remember a show that had a brother and sister who went back in time with their computer? The last show I saw was when they were in Rome and wore togas. I think they solved mysteries or something like that. I remember it was on early saturday mornings.