I think this story has the whiff of nonsense about it.
We are asked to believe that a British (presumably Caucasian) family travel outside of their beloved, exclusively white, country and then request in their presumably flawlessly plumb-British accents, that they are not be served by 'some Jonny foreigner with dark skin or some bally fool who can't speak the Queen's English properly, what?'.
I actually find this quite hard to believe - unless Prince Philip has recently been to the USA.
If this story is true then quite frankly, the British individuals in question are morons and should have their passports confiscated lest they travel and are offended again by the horrors of living in this thing that the rest of us call 'reality'.
But I suspect that this story is not entirely true and is a rather clumsy attempt at a stitch-up.