Setting Westminster chimes?

I hope this makes sense - I recently bought a 1930's clock with Westminster chimes but now its chimes are out of sync. It doesn't strike on the hour(s) in fact all the clock does, every quarter, is this:
Ding dong (six times). It's keeping good time.
I would greatly appreciate any help. I love this little clock and am so keen to get the chimes working properly again. Can you help?