Morris- the cam is one of the most loaded and wear prone parts of any engine so I don't think it's ever possible to over lubricate it.My thinking here was the std dribble past the followers seems to work ok for lobe lube so why not channel the over flow directly to the cam bushes rather than relying on splash for it to get there.I can't see it doing any harm.
The barrel is an ally big bore job from john Hill.Bored to 79mm {823cc].