I'm fairly sure it was Australian or American. It would have been on in the early 90s. All I can remember was that it featured children who had to save [insert concept here] through time travel; that the time travel itself was organised by a young woman, and that the time travelling was done through a clock in the shape of a man/android figure, which was kept in a shopping mall.
Does this ring any bells at all? Please? It's the only TV show I've still not managed to track down...