I've been getting on very well with 123. Yesterday the bodyshell was taken to 90% complete and today I've added the interior, using my usual method of fixing the seats and tables to the removable once piece floor / chassis which will also keep the glazing in place when the model is finished.
123 has been fitted out with what are now the standard FR Third Class seats, albeit in an unconventional pattern. At the Observation end - where in its guise as 101 there were fixed swivelling seats - there are now 2 x 2 longitudinal seats followed by a bay and a half of 2 x 1 laid out in the normal fashion. In this it is rather reminiscent of vintage Obs 11 (or Van 4 if you must insist on the current designation - still can't get used to it myself.)
The other change is that the seat backs are no longer all in line with window pillars, an unfortunate compromise which I suppose is a legacy of its original design to fit the much bigger Pullman armchairs.
You may also notice towards the rear (guard's comp) there are tip up seats where a wheelchair can be accommodated on each side and the folding oval tables - one is fully open on the model the other has half folded, as they were when Himself took some research snaps for me on the AGM train a couple of weeks back.