Sorry mate, the links didn't work for me!
Good to hear another Airsporter is giving pleasure and has been resurrected again, something very pleasing about restoring something - you put a bit of you into it!
The stock - seek a decent second hand replacement - they turn up from time to time but can be expensive for the Mk1s and 2s, indeed even the later marks, repairs, depending on the damage, can be difficult to achieve well due to the three piece design, I have a project Mk1 I acquired that still wears a mk4/5 stock that was fitted when I got it, my intention is to make a new stock - if I ever get around to it!
ASM