Jaz
You wrote
"Listening to the engine over the weekend it seems to come from the top end?
Any suggestions? "
OK a suggestion- MUCH MORE INFORMATION will really help. Like, you have had the car for 10 years and this just started to happen or, I just bought this car and, or after I changed the----- this started, or you know.
Take a short length of hose and try to locate the area of the noise and try to describe the noise. When you say the noise goes away when the engine speed is above idle do you mean goes away for good or does it return when the car is at idle again.
You have to be more descriptive if you want the right answer to your problem. Pete