The power delivery I have no idea about but the Gauge misting is something I get too and not just the speedo. I think this is because the gauges in cars like this are all small semi sealed modular items, not like the great big open things in normal cars. So they have their own little internal micro climate. The gauges on my Elfin Clubman do the same thing, so I am inclined to think that this is not really any lack of diligence on Morgan’s part, short of heating the gauges I can’t see how you can cure it. And finally and most importantly as the root cause of the issue, the glass on our gauges is real Glass not plastic, they will inherently be colder and more subject to misting. If you took the glass out and swapped for plastic lenses they would not mist up.
Aside from getting the flat spot fixed, don’t let the gauges niggle you 😄👍🏻