So my scooby has its turbo turned right down I'm told for Eco driving I'm not turning it up until I get it mapped but my dump value doesn't seem to make the right sound it just sounds like it's not using full power and being lazy could this be because the turbo is turned down?

It's a blitz valve and it has no damage

If you have low boost pressure it won't be able to make the proper noise i wouldn't think.

Low pressure = no noise !

Valve is there to release pressure , if you haven't got much pressure then not much noise

Yeah if you're running low boost or have a boost leak it won't go off .

my dump valve has a uprated spring ,so it just makes the turbo chatter at anything under 0.5 bar but when I back off the throttle at 1.5 bar it shhh's more than my mrs does if I talk during East enders [emoji4]

So in theory when I finally put one on my standard classic, the higher the noise would indicate stronger boost/engine and signs of a tight engine. :)  also signs of a well running turbo?