Evasive and Dishonest flat whites

I've never seen a generic chain coffee shop have anything other than some form of skimmed milk. Some have semi skimmed and skimmed; but whole seems to be impossible to find.

Was it an automatic machine, or was she frothing the milk by hand, from a jug?

Not so fast, little lady,” I said, “A flat white is meant to be made with full-fat milk, is it not ?”. 

I can imagine the conversation after you left; "a really helpful and pleasant man just kindly educated me on how to make a proper flat white, I'll be forever grateful!", or something like that!

if you actually said the words "little lady", that would account for the derision.

Also, what's so special about a flat white? Surely all milky coffees should be made with full fat milk unless otherwise requested?

I was being polite,really. Edgy, in the sense that you appear to be trying to give the impression that you don't care whether you come across as a complete arse or not.

If you look on the Frank & Honest website you'll discover that F&H produce "barista-style" coffee using the Eversys bean-to-cup machine that grinds, tamps, brews, adds frothed milk, and dispenses "at the touch of a button" - they may well not be able to handle full-fat milk, and I presume F&H won't train their staff up as baristas, so their staff might not be coffee experts.

Is this to do with the protein content of the milk and the lack of milk foam/texture that you get with full-fat milk sometimes (think it varies between winter and summer) depending on what the cattle are fed.

I still don't understand what is particular about a flat white over any other milky coffee, in this regard.

Surely, any milky coffee should be made with full fat milk, unless otherwise requested.