Hi everybody, not often I venture into this section.
I have offered (kind off) to service a friends original model 5. When it arrived it all seemed in good condition, putting out bisley practice pellets at 270 FPS (.22) so a little low but acceptable.
I was having a bit of fun shooting it in the garage and all of a sudden it lost all power and wouldn’t even push a pellet out of the barrel.
I’m guessing catastrophic main seal failure. So far I have removed the mainspring which seems fine. Looking at it, it looks like I now need to remove the trigger assembly to enable me to remove the cocking arm from the cocking slot?
I thought I would ask on here before drifting the pin out - what do I need to be careful of? Does the little trigger tension spring stay on the trigger unit or does it ping across the workshop!
Any advice appreciated greatly.

P.s Any idea where I can find a replacement seal? Both chambers and Knibbs are showing out of stock.