I have a bathroom UPVC window that has a worn bottom hinge and two
misted up DG glazing units.

How do I measure up the glazing units so that I can get replacement
glazing units?

How do I get the beading out of the frame in order to swap the glazing
units over?

How do I measure the hinges so that I can order the correct ones? I am
happy to replace the top hinge as well so its a matching pair.