Had a more leisurely examination today and you can remove the trigger group, although the sear has been welded down. I took the grip off to give it a clean, but it ended up looking worse than when I started. Fortunately replacements don't seem to be too difficult to find. Despite the rear of the bolt being replaced with a short length of steel tube, the cocking handle feels less 'wobbly' when you pull it back compared to my MkV Sten. Possibly because the handle can still slot through the thingamabob (name?) on the end of the return spring.