The world is the mollusc of your choice with kits, but the missing top hat probably isn't!
The TX is famous for getting it's top hat stuck in the piston with grease, if repeated energetic hammering the latchrod down onto a suitable wooden block doesn't shift it then we need "plan b"!
Take a small piece of paper and fold it in half a few times until you have a piece maybe 1.5cm long, fold it into a U shape and loop it over the edge of your spring, push the spring onto the top hat, the restricted inner diameter your spring now has should mean it will grip the top hat better, twist and pull out gently.
If that doesn't work we'll need "plan c", but we'll burn this ridge when we get to it.