My 01 Octavia vRS has started running rough as you like for about a minute after it's started, but is then fine apart from a very slightly lumpy tickover. The diagnostics light has now decided to stay lit (the engine shaped one, not the EPC) and I'm wondering if anyone knows what might be wrong? I know the good old coil pack problem would cause the lumpiness, but would it make the diagnostics light come on? Or is it more likely to be a temperature issue- it seems to run like the management system thinks the engine is warm while it's still cold- tickover when cold (after about a minute when it's stopped nearly cutting out) is around 900rpm, which is the same as when it's warm.

Thanks for your help!

yes the coilpack will cause the diag light to come on and cause all the symptoms you describe.

I have some spare coilpacks.