Well I got the barrel drilled out yesterday. When I drop a reloaded round in there now it sits nicely flush and it's much easier to extract than before. I haven't taken it to the range to play with yet (Saturday, hopefully) but I think it should be fine.
Ended up not costing me anything - gunsmith guy did it as a favour for the projectile guy ... got to laugh :) ...
I think I'll take my gun into the gunsmith next week and leave it for him to do the hammer, sear, ambi-safety & mag well rather than waiting for my friend (mentor) to do it. He's got enough on his plate and as I'm away in Sydney for a couple of days it's a good opportunity.
Then, hopefully, that should be everything I need to do to the gun.
I'll post pictures when it's finished.