Thanks again for the replies all.

I did the shock top-mount bushes on the weekend and they were easy. Took about an hour all up. The noise is still there..

I'm going to put my old front springs & shocks back in the front only and see if the noise remains. That will only cost me a small amount of time, but no money. At least that way I can tell for sure if it's the shock. Then again, it might not make the noise as the original suspension is so much softer. It's worth a try though. If that fails, looks like i'll be buying some bushes from eBay!