Nice post glad we've finally found the answer to this & I'd bet a few of us have learned something new also from this. I've never heard of a pressed-up camshaft before, that's frankly absurd IMO. I wonder what the reasoning behind it is, since I'd have thought it'd be more expensive and labour intensive than having a one-piece cast/forged item as per normal?
Jay, well done on sticking with it and seeing the job through! This is one of those things that's fit to drive you nuts, for most of us I think the camshaft being "right" is/WAS pretty much a given as long as it wasn't worn or snapped!
Thanks. If you're interested in the DV4TD engine there's a great YouTube video here
Alas it's in Spanish (I think) but at 8:50 it explains (thanks to translating the subtitles) the camshaft is actually hollow and the lobes are pressed on - all with the aim of weight reduction. I agree crazy! But it's funny how things turn out and certainly saved me and Jay from messing around taking the head off and regrinding new valves thanks to that weak link!