Never heard of a CVH cam going after only 10,000 miles

If i remember right, the last owner of your car didnt use it that much? if that was the case it could be that now the car is doing some mileage it has loosend up a bit, causing the tappets/lifters to make a noise.

Does it make more noise when its cold or just when its hot?

How many miles has the car done now.

when was its last service?

If it comes to it fitting a cam and followers is a very simple job, anyone who is reasonably competent with a set of spanners can do it.