I just had to give the Wynne's stuff a go, got to Halfords and there's about three types.
1. One you put in the oil to aid valves.
2. One to put into a full tank which cleans jets.
3. One to put into a quater of a tank which cleans, lubricates and protects jets.
I purchased 2 and 3, put all of 2 into half a tank and already noticed smoother drive on my 60 mile drive home, also tick over feels smoother. I'll find out in the morning if it starts 1st time and sounds smooth but I don't think it will clear the chuffing sound which I thought were leaking jets but can't locate it, mechanic checking it over tomorrow evening, will keep you posted.