One of the problems with Morgan volumes is that development is inevitably less thorough than for the high volume manufacturers. This could lead to issues such as slight errors in hose shape causing excess stress on the fittings of modern plastic and polystyrene radiators.
I think you are right on main street Paul. In my experience all low volume products are always more prone to have these kind of issues. They just can't afford to spend as much time and money in designing and testing products as their high volume counterparts. Don't forget the Plus Four is a completely new car. But what they lack in reliability they make up for in charm and the idea you drive a handmade, bespoke product made by real people instead of robots.
On the Caterham forum someone posted the answer from Caterham to a letter of somebody who was complaining about some quality issues. They responded that they do their very best to produce the best products that they can. But if they can't live with these small defects they should buy a Porsche 😀😀😀😀.