I go with the 185/70/15 Avons, yes they are pricey but how often do you change tyres on a Morgan ? Safety is paramount for me and the Avons are super sticky even in the wet. My life is worth £1000 every 5 years.
I have looked for these but they are not available - all I can find in this size is P6000 which I’m not keen on. And I do agree re safety - with only 4 points of contact I want to make sure the road to car connection is as good as possible