I haven't had mine apart in a long time but here is what I remember. You can unscrew the end cap on the shroud (heat gun on low to soften the adhesive the first time), and then use a pin punch, nail, small screwdriver, etc. to loosen and remove the spanner nut inside the shroud and then shake out the baffles. When you reassemble it, don't try to torque the spanner nut down, just snug it enough to keep the baffle stack from rattling around. If you have the manual there is a diagram in the back.
Or you can take off the foster fitting dust cap, remove the barrel band, and unscrew the entire shroud and shake the baffles out of the breech end of the shroud, that way you don't mess with the spanner nut.
Get a hold of JTS and see if they have spares, or if you know how to 3D print you can make your own.