Sorry, this is a TV show rather than movie - hope that's okay.
Early 1970s, British origin, about a pack of street kids with a sort of creepy Fagan-ish uncle who lived in a junkyard/Rube Goldberg compound. The only things I clearly remember are the uncle - sort of a John Cleese in a ratty top hat - and the gate to the compound, which had this bizarre mechanism with spinning bicycle wheels and the like that opened and latched it.
Possibly "Here Come The Double Deckers!" from circa 1970.
http://us.imdb.com/title/tt0066669/ (http://us.imdb.com/title/tt0066669/)
I can't find quite enough information to nail it, but this certainly looks like the right show. Thanks!
It's weird stuff to google up under that name...
No problem! :thumbup: