Good news on the emission tests, as she pops like a good 'un on deceleration so I know the mix isn't quite right . The pipes make the garage floor shake (which is what I was after when I bought them). I wonder if I should find a Harley specialist - I know of one who will pass just about any noise level. It's the first time I've put a bike through the MOT, so just a bit apprehensive of what they might find!

Thank you for all the replies - a mine of information!