As above I have a slight chatter noise at low revs. Seems to disappear at 2k to 2.5k revs or could be that I can't hear it over the exhaust noise etc

Is there a way to find out if it's the turbo ? The turbo still works fine and kicks in as it should. The noise does seen to come from that side if the engine though

I don't have any clue but maybe a recording would help if you could get one, so people could hear the noise.

Is it always there or disappear when warm?

Did you put the heatsheild back on after changing the downpipe, Maybe come loose ?

Either heat shield rattle which is most likely

If it's doing it from cold and disappears more when warm then might just be a bit of piston slap

Thanks for the replies guys. Just had a closer look as I pulled onto drive from work.

I think it's a combination of slight heat shield rattle and a blow from joint between mid and down pipe.

I'll try and find time over weekend to sort it and update