No, not really. The engine is just generally "Tappitty/rattely" IYSWIM.
Its not bad, just irritating.

The car is high milage (100,000 plus) but otherwise in good (Excellent actually) condition. The noise is noticable but not really bad enough to justify any extensive (Or expensive) investigation.

This is one of those situations where I cannot believe I am the only person who has seen this and am just wondering how others might have experimented/dealt with it.

I am minded to try a racing grade oil as an experiment (EG 10-50 or 10-60 even) but I am concerned that I do not know if there is likly to be a down side

(My past expriance is that ZETEC type engines do not work well with "conventional" thicker grades of oil such as 20-50 (I have never put 20-50 into a ZETEC but I have come across customers who have done so, and it is not good!))

As I said, I am just wondering what others might have tried before me as it were.