Also, how many people buying a Morgan for the first time would buy privately from someone they have never met before? Most will go to a dealer.
Despite my best intentions, this is exactly what I did when I bought my Roadster because it was the right colour combination. And as it turned out it was the right thing to do (hindsight again!).
Dealer specced cars (with the exception of BHM) tend to be conservatively coloured, so usually a mainstream (usually dark) metallic with pale interior, so the unsold new cars mostly fall into this bracket.
The theory being that these will sell better than offbeat colours. But personally I would only be tempted by a bright colour with black interior. These are rarely built by dealers.
The factory ought to build a set of cars (Eg Narrow bodied Plus 4's)- one of each standard colour, and rotate them round the dealers as demonstrators.
Yellow or orange? mmmmmmmm.