I haven't put much thought into this so could be writing bollocks,but if you ground off the tab from the trigger block
and left out the tabs,so the block is only held in place with the trigger pins,to remove it you would:
Remove the stock.
Screw the front trigger bolt back into the cylinder to take the spring pressure.
Tap out the trigger pins.
Place the trigger block end on an old seal or some such and press down whilst undoing the trigger bolt.
Bollocks or genius?