Just picked up a Smith Enfield westminster chime mantle clock. 

Anyone know how to regulate the chimes on a Westminster chiming clock? It strikes the hours correctly, the quarter, half and three quarter are perfect, apart from being 2 chimes out. So, for example, for the quarter hour, instead of 1..2..3..4 it strikes 3..4.. and then the first two chimes of the half hour set. So, it’s 2 chimes behind where it should be. Any ideas?