Spiral,
Thanks mate, Its a rough old thing but I do think it has some slight possibilities...

I've got a nice slow bench grinder to do the shaping, then I'll file the edge again.
Mross,
I'm a little worried about the straightening it. My usual method is what we call over here a 'lump hammer'.
Louie,
You're probobly right, I just have a problem resisting the urge to 'save' those hard luck cases!
DhaDha,
By weird conincidence, I noticed that mine also has a mark on the blade. Same as yours but two, back to back. Whats the significance?