Can someone guide me here?
I thought that the difference between a Cornish and a Devonshire Cream tea was that the Cornish was made with crusted clotted cream, and and the Devonshire version was made with thick whipped smooth (white) cream.

If you're not able to satisfy your craving in a real ye olde tea shoppe (no insult here, I'm as partial as any visiting tourist to high tea in the rainy Cotswalds next to roaring log fire ) the only sensible suggestion would be to find a decent supermarket and do a DIY version on the trip home - the tea will be appalling, but a small tub of clotted cream will make even a supermarket scone taste nice.

Think I'll take a 'high tea kit' along for my next flight