I am getting a tappety sound (quite loud) when traveling at reasonable rpm, eg motorway driving, but no at low rpm. Seems to come as the car warms up.

On startup the car is not unusualy tappety for a cossie.

Is this the tappets knackered ? or would that show when the car is cold and started.?

OR
could this be a sign of camshaft issues, .....the car runs fine by the way.

advise appreciated.

Dave