You originally said it makes the noise under load ie while hard excellerating? it could be as simple as just "pinking" which sounds quite metallic like valve clatter.
Long time since had a petrol vehicle but can be down to timing or mixture issues.
Can result in burnt badly pitted valves, sounds like you are going to get right in there so add these checks to all the others.

You might want to look at the state of your rocker shafts before going all out for a new cam. I've had V8 Rovers for years now and the shafts suffer from poor oiling and don't last. Substantial wear in them can lead to the Hyd Lifters not being able to compensate - hence tappet noises. General feeling is there are plenty of 'cheap' shafts out there - just buy the best you can afford. Try RealSteel in Middx. All the best.

Cheers All.

Forthbridge - that was pretty much where I'm at at the mo. Get the intake and rocker covers off so I can at least see the cam & rockers, then make the call as to what needs to be replaced.

SmileySteve - Thanks, but I'm fairly certain its not pinking (had that on other cars where you could actually change the timing!) - no overrun when I turn her off either.

Oil pum,p I'll look into if I have to get her that stripped down.....

Will hopefully be able to start in a couple of days.........