Name of a (possibly made for tv) fantasy movie that aired lots on Family Channel in the 90s/early 2000s

Hey y'all, I've last asked this question probably some 20 years ago to no avail, and this movie still holds a place in my heart so I figure maybe by now someone might remember something!

The movie itself used to play in the evenings/extremely early mornings (because I have a friend who would sleep over as kids and we would secretly stay up watching TV, as kids do).

It surrounded two English children, likely twins or at least siblings, who I believed lived in a country cottage style home with a grandparent. 

I have no clue how this ball gets rolling, but eventually they befriend a dragon, are sent around the world to locate these gems/marbles while being chased by martial-arts trained goons who are also after the gems.

To get around the world, the trio (kids and the dragon) would end up above the clouds and used some sort of minecart/rail system if I recall correctly.

I seem to remember a scene involving a chase/fight in a canal on a boat at one point.

I sincerely apologize for I am now 31 and my memories are forever gradually fading as time goes on.

Thanks for all and any help with my investigation!