losing the marbles?

at my parent's house we have a marble run, which was given to me for my 7th birthday, we love it and got years of fun out of it as children, now my son and nephew get just as much fun out of it....the only problem now is Rosie...we have to only play with them when she is asleep, and we have to count the marbles out of the pot and back in at the end of play...

...Jonny gets quite fed up with this routine!!!