Well this is really fun...
They are really nice models.
Absolutely captures the real thing, and runs very nicely.
The Mark 3s are slightly less free rolling than the Pullmans, but still very free rolling I would say.
Absolutely none of the problems I had with derailing when using the Pullmans for testing.
I originally planned to get just three carriages (no restaurant car) as I thought the four car train would be a bit silly, given (as you can see) it's far longer than any of the straights on my layout.
But then I realised it would *just* fit in my long curved siding with four cars, plus the restaurant car is very nice model, oh and I had enough Hornby points to very nearly get it "for free"...
I'm pleased I did, I gives it the gravitas of a proper rake without being totally absurd for a very small layout.