Hi
I have just stripped a Gilbert movement for cleaning however I have have come across a problem. The half hour is on a passing strike but this is not happening on the half hour it is on the 25 mins to. Though the hour striking does commence as it should on the hour. Would anyone know how this can be rectified / adjustments made. I have added a couple of pictures if these make my question clearer. 
Many thanks for any help and Happy New Year.
Martin

