I've just rebuilt the head on my wife's Polo, and now everytime I start it from cold, there's a noise that sounds like a loose tappet, but as you rev it, it sort of has a 'squeak' aspect to it - imagine a slipping drivebelt but much less severe. Once it's warmed up a bit, it's a lot quieter, but you can still hear that one slight 'tap tap tap tap'. I'll record it tomorrow and put it on here so you can hear for yourselves, but meantime - does it sound like anything other than a wonky tappet ? Do these things clear themselves in time ? The oil I took out of the engine was pretty shitty and thick - I've just filled it with semi-synthetic 10w40. Should I leave it a few weeks and see if the new oil clears out the dodgy tappet or should I just accept that I've got to buy a replacement...... and take the bloody camshaft off again etc... !

Did you replace the water pump when you did the head? The squeak makes me think water pump, but the tapping I don't know. Get the end of a screwdriver onto and around the head to see if it's head related or not. Nothing loose under the cam cover? Or anything at all?

Yeah, I changed the water pump at the same time. It's definitely in the head - I'll record it tomorrow - much easier that way ! I'll take the cover off and check with feeler blades when I have a spare moment.

Just trying to give you some hope

Mine can sound tappety in the mornings but definately goes away once its warm. As you say, recording it would be the best thing.