It deffo works!! How isn't your egr coming off?? 3 Allen bolts seized?? If so spray them with some plusgas/wd40 then try tightening further to crack rust then go and have a cuppa. They will come off then!!!
Terraclean costs a fortune doesn't it?? This is only £10!!
Shame your in Aberdeen pal, I'd have helped you to do it its so simple it's unreal, the difference is immense I'd still look at removing your egr for a clean and a blanking plate, you could spend all that money on terraclean and the egr will still get dirty down the line.
You won't need to remove inlet manifold to do mr muscle, I'm just going to down the line as I know if my egr was stinking dirty, my inlet surely will be!!