When i slow down in my car for roundabouts/ junctions then speed up again it splutters for a bit then drives ok till the next time i do the same?

Its old but I will answer anyway, open bonnet, look at coil pack on right side of the engine as you look at it, (its the black unit that the leads from the spark plugs are plugged into), sometimes you will see a small white strike or crack on the unit which would indicate it has failed (although not always). To replace pull out the electric plug at rear of the unit, and also remove the four leads from the top Remembering the original position of leads. Four small screws with star heads hold the unit in place , remove these and install new coil pack (about £60 from any good motor parts supplier) replace leads and rear electric plug and off ye go. Faulty leads and spark plugs can also cause the car to chug so new leads and spark cannot be ruled out but the coil pack is a common fault up to 06. TIP: tip ex the date on to your new coil pack so you know exactly when fitted because some do die within a year, and you can get another under warranty.