First's 'GWR' prestige refurbishments come top of my list.
The GWR first class Mk3 interior takes my top award, as it was a huge improvement over the bland First Great Western 'upgrade', and a genuine transformation that felt luxurious in an era when interiors were generally becoming more austere. The seat trim detail looked expensive and felt softer, the warmer lighting, winged headrests and smoked glass dividers made it feel more cosy. And when laid up for dinner with outrageously anachronistic old-GWR-crested crockery, I cannot think of an interior I would rather travel in.
An honourable mention must go to their smaller scale, but equally ambitious, refurb of the Night Riviera sleeping and lounge cars: again, a radical transformation of Mk3 stock with cunning details like the folding ladder (though I wish they hadn't turned the beds round and had kept a luggage shelf by the basin).
Brickbats to the same company, in the shape of FGW's standard class on the Mk3s: ruining the spacious feel and views out out of the windows with super-high backed seats and a cold colour scheme matched to cold lighting, and far, far too few tables. Scotrail have showed how they should have done it.
Dishonourable mention to the interior that never was: the eye-popping horror mish-mash of the
prototype interiors put on show by First Great Western which looked like a fight had broken out between three colour schemes (which I suspect it had). Purple meets chartreuse meets brown meets turquoise meets blue meets grey? Just no. Mercifully never rolled out - though the stylish buffet redesign did make the cut.