Cat light / misfire on cylinder 8 problem.

[jools_s8]

Thanks for the replies guys.
@Goran - I have no idea - the car has a stamped history book but no bills, so I presume never. Thanks for the info on the cats - as a pre 2001 car, the cost of replacing the cat using a non type approved type is more bearable as well. A new lambda is between 40-70 quid depending on whether it's bosch or pattern part. I am not going to attempt doing an injector swap as I know my limits too.
@ainarssems I am trying to borrow a multimeter this weekend as found my aged old MM has died a death due to being packed underneath something heavy in our house move years ago. It is going into my trusted specialist Tuesday morning.

It started fine just now with CAT light on. No lumpiness. A stop/start saw it start fine with the CAT light going out. Without getting it upto temp, I am about to go swap the plugs and coil packs around anyway. I doubt this will make any difference. NGK -R plugs, same as whats in there now. At least I will have removed the possibility of failing coilpacks or plugs from the equation.