Of Lanchesters...... We used to shoot one quite regularly at work using standard issue Mk2z ammo and suffered with a lot of misfires due to the caps not being fully punched. I mentioned this to one of our regular visitors and he suffered the same. But he cured his by inserting a grub screw through the side of the bolt, locking the floating firing pin block in place. Effectively making it a fixed firing pin working on the API system. Did the same to ours which cured it!
You mentioned early barrels Vince. Yes....., it prompted the memory cells that the Navy Lanchesters that we encountered from Sembawang did have two sorts of barrels but we only had the sort that were secured from the top. There was a drawing to convert these 'front-fix' barrel guns to top-fix to suit the barrels that were supplied. I have to say that the quality of the spare butt stocks was awful! Not just the interior but externally too!