Unlike Mr Grumpy and GavChap, I and the rest of the board have not had sight of the the effects of the perceived problem.
OK , we have had these descriptions
"it starts about half way down"
"brown from halfway down"
Now both these descriptions are still not "definitive" as it could be equally interpreted as being..... brown upwards from halfway down or brown downwards from halfway down...
Whereas one photo would have remove any doubts as to what is being described.
All this effort and time wasted just in guessing what the plugs leads look like
Anyway whatever, all I will say is this. Changing the plugs and leads is a wasted and costly exercise, as it does nothing in regard to fixing the problem. The discolouration of the leads can be wiped off, either way it is only cosmetic and even left un cleaned does not effect the insulation properties of the leads.
Even though my two plug port wells had a third of a jam jars worth of water in each of them. The ignition sequence side of the combustion process was unaffected. The water ingress only came to light when the plugs [ having been replaced 12 months earlier by the selling Ford dealer ] were inspected by me at service interval.
Once I solved the water ingress problem [with new revised washer jets and a smearing of silicone grease ] I removed and inspected the four plugs [they were in perfect condition] cleaned the 5 year old original plug leads, that had been subjected to this water contamination, for those past five years. With it being an early build non rectified known design fault [ don't you just love these Ford Dealers stuffing you with £80 hourly rates whilst ignoring rectifying known faults]
Anyway here we are 21 months on from the fix, spark plugs now been in the engine 2 years 9 months. And the original plug leads subjected to 5 years of sitting in water, are now just 3 months short of being 7 years old, and never missed a beat the all the time I've owned the car.
Mr Grumpy, you have not indicated in your postings that you are having any problems with the ignition. So why on earth spend money replacing parts that are functioning satisfactorily ?
No need to answer mate, it was a rhetorical question, I'm just trying to make you see the logic of my argument. That replacing perfectly functioning parts with new parts, fixes Jack Sh@t