Hello,
A friend of mine is in desperate need of a replacement hammer assembly, i have not had much luck with having scoured the internet.
Can anyone of you erudite gentlemen point me in the right direction, please.

Thanks in advance....

Might ask over on the British Militaria forums:

https://www.tapatalk.com/group...ariaforums/index.php

Here you go:

Webley Mk. VI Hammer, Complete

Sometimes I think Numrich has everything.

Sorry. I read Mk. IV as Mk. VI. Just realized my mistake.

Here is the hammer assembly, but without the firing pin:

Apex

They don't seem to have any firing pins.

Good luck!