Does anyone remember a children's TV show, where there was a oy and girl, and they travelled to different era's in time. Think there may have been a cave alomg the way. Had a catchy theme tune?

Von, I don't know if you are thinking about a British or U.S. television show. This website lists all the television shows about time travel. Television Shows About Time Travel (http://www.cvil.wustl.edu/~gary/SF/time-tv.html)

The one on the list that appears the closest to what you are describing is a show from 1970 called Timeslip. http://www.imdb.com/title/tt0154091/

If that isn't the show, you should be able to find what you are looking for on the first link in this response. :)

Great site Lemming - I found this on there, maybe this is the one? The Young Jacobites (1960)
Two kids vacationing in Scotland entered a cave and found themselves 200 years earlier in time. They eventually helped Bonnie Prince Charlie escape to France.