I know Holland & Holland built some rifles on the P14 action. I also remember seeing an old catalog with a picture of their "Best" magazine rifle and it was built on that action. Based on that, I see no reason to believe other British makers would not have been doing the same, including Westley Richards.

Strathcona has a good explanation, this may have been a barreled action that found a new home in a sporterized stock.

Alternatively, and maybe more likely, this rifle may be wearing a take-off barrel. The barrel might have been removed from a Westley Richards rifle that was being rebarreled, probably to a different caliber. That would also explain why the sights are gone. They would have been removed to be mounted on the new barrel. It also explains why the bolt handle has not been altered. Is there a Westley Richards serial number engraved on the tang or triggerguard? If not, that also supports the notion that only the barrel is from that firm.

What about the proofs? Wouldn't a BSA action and barrel likely have been proofed in Birmingham and wouldn't a Westley Richards barrel and action likely have been proofed in London?

So, if the barrel and action both carry London proof marks wouldn't that support the notion that the barreled action was originally built together? And, if the barrel carries a London proof and the action carries a Birmingham proof would that not support the notion that the barrel came from another rifle?