Hi I'm having problems with my mondeo.

I had it serviced and cambelt replaced and around 1k miles after it gained a rattle sounds like hydrolic tappets so my garage replaced them and it still has the same problem the engine runs fine no loss of power. When the engine is cold the tapping noise is very faint but once up to temp it's loud. It does come and go sometimes too. Small ends have been ruled out has when you rev it the noise goes. My garage has done an oil pressure test and the oil pressure is high at 2k revs I believed its 5bar but I might be wrong just going on what the mechanic's said while chatting. They have flushed the engine out and given it another oil change.too.The car is only on 120k miles. I've not spoken to the garage since Wednesday as the mechanic went on holiday. There was a lot of scratching heads and they are stumped. Just wondering if this is a common problem or if anyone else has had the same problem before the garage start stripping the engine down.