So a quick update on my original post above, I ordered and have had fitted a new H&S cat back X-pipe exhaust and the difference is night and day over the old one, just wish I had done this before. The exhaust the car came with was also H&S but was just 'wrong' - it was probably an early one and may have been a dud, or got second hand a bit bashed about and fitted to the car, but certainly it had been installed badly and was blowing from the joints where the different parts were connected. Like I say the other one was just crap, so glad it has restored by confidence in H&S exhausts. Anyway, now with a properly connected and sealed exhaust, the wonderful melodic feel base sound the car omits is fantastic, so glad I had this done! 😀