Sam H

you will struggle to change a single bit. the units are pressed together and then hot melted around the edge to prevent the units breaking down. of course yours might be different though. it would be easier to change the unit. 11yrs glass experience

ahhh re reading your comment are you looking to split the unit ?

go outside measure to the outside of the beading width and height take of 10mm of each if your any good at guessing measurements gauge the metal spacer inbetween the glass panes if not you will have to take it out get a blunt chisel or 1 inch scrapper prize 1 corner of the rubber gasket out

and peel it out do all 4 of them go back outside and push the unit back then the beads will come out easy to put a unit in just reverse it put unit in put the beads back go inside push it forward...