Diesel sounding!

Hi,

I've just had the octy serviced (80,000 mile on monday) and when I got home from work last night I noticed that at tick over my engine my engine now sounds a little like a diesel which stops when you increase the revs slightly.

I've just read that it may be the hydraulic cam lifter but should only happen from cold? The noise seems to be coming from the cambelt side of the engine at the top.

Is it anything to worry about or will it go?

I've only done around 30 miles since the service.

I think they used Fuch's titan supersyn oil which is o.k for fixed servicing as far as I'm aware.

Other than that the car runs fine, it's a 03 VRS by the way

Joe