Did a few more checks after changing a couple of other things and breaking down and being towed home by the missus
it seems the engine is permanatly dead now, which is a good thing I guess as it should make diagnosis easier.
I checked the spark at the "King" lead (Dizzy end) by connecting an old plug and earthing it out and all seems OK "Sparks"! I checked each of the HT leads to the spark plugs and am not getting anything, this means the problems with the dizzy cap and rotor arm or the HT leads....Yes?
These two items where replaced two weeks ago and I wouldn't have expected them to fail so soon, but I stripped off the cap which looks OK and the rotor arm again looks visibly OK. I started to check for continuity and found it OK on the cap (buzzed through OK) but when I checked out the rotor arm I was getting a high resistance between the center and outer terminals. Now I'm guessing here as I'm no electrican but is there a Capacitor or condensor between the inner and outer parts of the rotor arm, there is some sort of resin btween the two?
The other thing that I noticed was the amount of gap between the rotor arm and the 4 terminals in the cap (approx 3mm) this seems excessive, am I right to think this?
Summary of things I've changed this weekend.
Checked all wiring
New spark plugs two weeks ago
New Distibuter Cap and rotor arm two weeks ago.