Great news Steve for another year.
They must have been really picky at the place I went to last time, they gave me an advisory for noisy exhaust (milltek non-res)
I had this also. An advisory for having a noisy exhaust, no advisory for about three years, and then failed on it because apparently "the regs have changed and if it's louder than standard it's an automatic fail" - which I later found out was wrong - and had to bring the standard exhaust through for them to switch over. I've gone to another garage since, and always left the standard one in the boot, but never had any comments put down about it.