Xj12 series II door window replacement

Hi guys, im new to Jags just picked this one up and two weeks later some a**hole smashes the passenger front window… I managed to find a replacement window and get it inside the door with the regulator hooked up, but had to take the front track and quarter window out to do so, now i cant get the track back in! Is there a tip or trick to doing this? How did they ever manage this at the factory?? Thanks in advance.

The glass must be as low as possible(remove bottom stop and detach regulator & arm), then insert quarter window and track with tack pointing towards front bottom corner. fit quarter window into upper frame and engage glass into front AND rear tracks. Fit the two bolts and spacers to secure. Fit regulator arm to lower glass slot and refit regulator to door.

Cheers, Mike