Hi holly, I have had a similar problem with getting the top hat out (if present)
For some reason (physics wasn't my strongest subject) instead of tapping the latch rod onto a surface to free it up, grasp hold of the piston and hit squarely upwards with a piece of wood onto the bottom of the latch rod. This worked for me, I had really stubborn top hat to remove from one of my TX's
P.s when you tire of the SR, let me know and I'll take it off your hands.
ATB.