Steve,
When you have the distributor out, check that the bushings are not worn and the shaft cannot wobble about. These conditions could result in a short circuit problem such as Vanden’s.
Good news, I like my +2 again - A new distributor and coil and the lumention removed (for now anyway) and it appears to be cured !
A few more weekends to build up confidence in it’s reliability and then I’ll get a few track days booked.
thanks again for your help.
Steve
For anyone with an understanding of the functional difference between any electronic ignition and the breaker point system, the clear winner would always be the breakerless ignition. That there’s so much passion in the other direction here is quite odd.
You don’t see many people retrofitting breaker systems to their Toyotas and Hondas these days, do you? 
I suppose it could be the case that Lumenition is a very poor example, but the happy users suggest otherwise. I suspect the real answer is bad connections or other improper installation.
I made the switch to Pertronix (I think this is same as Aldon) from a perfectly fine breaker system and would not go back the other way. No wear, no timing drift, no hassle.
You do need to lubricate the distributor, but all of the other headaches associated with breaker points are history.
Don’t listen to the naysayers – while the original system does work if properly adjusted, the electronic systems perform better, are more reliable, and require no fiddling. These attributes are inherent in their design. The sole benefit of the breaker system is that failure of the electronic system without a spare will leave you stranded, while points can usually be cobbled to get you home. In a lifetime’s driving to gain that advantage, you’ll be doing an awful lot of cobbling with your points. My last stranding caused by electronic ignition was in 1985 and my current car is closing on 250,000 miles without touching the dizzy except to replace the cap and wires at 100,000 mile intervals. Try that with points.
Of course you’re right, and the same applies to fuel injection vs carbs, electric headlamp lifters vs vacuum, solid drive shafts vs rotoflex, zetec vs twincam etc. etc. As one of the naysayers (what a great word!) for me it’s partially to do with simplicity of diagnosis, and partially to do with originality. Although in the case of points vs electronic ignition I must confess that the balance of argument is 99% simplicity and 1% originality for me!
Each to their own of course, but surely the term ‘clear winner’ depends on why you have a 35 + year old car in the first place?
I think that we’re all long overdue for the old originality vs improved debate. I doubt that there’s a topic that stirs up more passion amongst old car owners. who’s going to start the new topic then? 
Mark
I think it all depends on personal experience. A year ago I would have laughed at the naysayers and thier foolish old fashioned ways, because I had a superbly reliable and hassle free lumenition electronic ignition that had proved itself to be foolproof… So foolproof in fact that I had complete confidence in it and assumed that whatever sickness had belfallen my dear Elan it couldn’t possibly be the electronic ignition because it was a sealed box and couldn’t go wrong. I had in fact checked all connections and found no problems.
After months of faffing about I have now changed my ways and will humbly rejoin the racks of the naysayers with my old fashioned points that work.
(Although I won’t go as far as to revert to rotoflexes and vacuum headlamp lifting …yet)
Steve 
Perhaps just an associate member, Steve. I was a founder member up until a year ago, and some heated debate on this forum opened my eyes to the Zetec Plus 2. After trying a few, I concluded that the well built properly engineered ones are fabulous machines, whilst the built-up from a scrap Mondeo on the cheap one are horrendous things. But then I then bought a '68 Plus 2 from it’s original owner, that was fitted with a BDA in 1971, and fettled for a while after to get it right. The installation was done properly, by engineers who know their stuff, and it feels like it belongs…and after 36 years it’s become original!
And just to make the electronic ignition enthusiasts grin, it’s fitted with a Lucus Opus system, the granddaddy of electronic systems. They had a terrible reputation in the Jag V12s, would last 1 rally in the works Escort BDA cars, but it’s still doing what it should in the Plus 2…36 years on.
I don’t know what I’ll do if it goes wrong though 
There’s always the old points of course.
Mark
I carry a spare dizzy cap, rotor arm and set of points (and cap) pre- wired with the screw and washer etc. I have lamp screw driver and figure that it my Aldon did fail I would quickly revert to the old points (time up rough with static and lamp) to get me home.
Does that not give you the best of all worlds. Also if I think something is giving me the Sh*ts I put the points in to eliminate the electronic ignition or not.
It has been discussed here before but I think Luminition are quite sensitive to coil resistance and do fail if the letter of the instructions are not followed. I had one fail on plus two I had because the coil resistance was to low. Lumination had it back and gave me a new one. I matched the coil with a small resistance and it ran for years. When I checked the car history, it had failed before. Missing at about 3k RPM.
Mike 
Mark,
I will go with you. points etc work when ok. Friends with elec’ ign on old cars have had curious problems usually to do with earthing. One point if not made before is that currently available rotor arms are c**p, change every year and if the car stops or stutters change it anyway.
Ian
Could it be as simple as fuel vaporisation (how do you spell this…?) ?
When engine is cold, no starting problem.
When parking the car when engine is hot, fuel in fuel line and carburators will/can vaporisize, and the car won’t start.
Can be cured by fitting a heat resistance shield between the engine and carburator, and move the fuel-line to a ‘cooler’ place in the engine room.