Drop me a PM and I can get the headset parts out, possibly tomorrow (wait - just found out you're in Australia. Eek. I always have issues with international shipping, I'm not confident in sending this one out).
That said, I remember seeing (I think) JohnDThompson mention he may have a top nut that could work out in this case, but ... dunno what the result was. Real life has been super busy these last couple weeks so I haven't had as much time to catch up here at BF.