Rough running. engine runs very rough, bit like driving in fith gear at twenty miles per hour,engine toxic fume filter system warning light is on,{little picture of engine} also heavy on petrol,abouy 25 miles to gallon,is this a diy repair.

Before replacing all 4 ligt them one at a time by removing each screw starting the engine and lifting them one at a time. you may only have to replace 1

Yes, it is a DIY job. Fault is usually caused by water ingress damage to the coil packs. There are individual pencil coils for each plug which are held in place by a torx screw. After removal, check and remove any signs of water inside the recessed spark plug tubes. Replace the 4 coils and spark plugs and the problem should go away.