For the benefit of others...
Over the last 3 days the car started sputtering intermittently (idle and acceleration) until it consistently behaved like running on 3 cylinders (shuddering - idle and driving).
Confirmed that cylinder 1 is not working. Checked that cable resistance which was OK - so it's the coil pack.
Already happened once at 300k km. The used replacement that just went bad only lasted 10k km......so replaced with a new Intermotor aftermarket part (OEM PN#12131247281) which was in stock locally:
http://www.ebay.co.uk/itm/Ignition-Coil ... 5d51389a99
