Picked up a new customer who has two types of secondary glazing. First type (slides left to right/right to left) is easily popped out by lifting upwards slightly but the other type is more like a sash window style, sliding up and down to open. I couldn't see how these sash style panes are removed for cleaning as there is no obvious gap/recess to allow the pane to pop out. Anyone dealt with this second type before and how can the panes be removed?
Thanks.