Replacement double glazed glass tight fit.

[Westindieman]

The old unit got water in and had to be replaced was very tight in opposite corners (top right/bottom left) so I think the frame may have shifted slightly. When I gave the measurement to the suppliers where I was having the glass made I shaved about 5cm off the sides but it seems the tolerance they allow have took my glass back to really tight and I cant get it in without some sort of force. Is there any recommendations to help me sit this properly? Can use some wood and hammer on the side to bang it in or is there a tool I can use to help me force it in? Any tips please?