Got it sorted. I fitted the tightest, right side, first so it was snug then fitted the left. Leaks are now gone. Also swapped out the O2 sensor while I was under there.
Along with a new set of plugs, air cleaner and MSD leads, it now runs the smoothest it ever has. Just waiting on a new MSD cap and rotor to turn up as well
But now as usual, as well as my dodgy hearing not helping, you fix one problem and find another. Now that the exhaust noise is gone, I can now hear a ticking lifter.
Thanks again for the reply, Peter