Got my 'First Class' CrossCountry coach (ND-226B) in the post from Hattons today... in reality it is, as Robert says above, the TCC (Trailer Catering Composite)...
A few observations regarding the XC HST and it's matching coaches - given that each XC HST has 5 vehicle types in each rake - TGS, TSD (Trailer Standard Disabled - some with blanked off windows), multiple TSO (Trailer Standard Open) - 3 or 4 depending on whether you want a 2+7 or 2+8 HST rake, TCC and TFD (Trailer First Disabled), I think Dapol has done rather well in producing each type of vehicle (bar the TGS of course... yet!) - the TSD and TFD come in the box set with the power cars, the TSO is available as a single coach to buy however many you want/need, and the latest "first class" vehicle is the TCC - leaving only the TGS to deliver.
Usual formation for 2+8 is TGS-TSD-TSO-TSO-TSO-(TSO*)-TCC-TFD *omit for a 2+7 rake
There are painted over windows on the TSD, TFD and TCC are in the correct place for disabled toilets/catering areas depending on the vehicle in question (panelled over and removed on the real thing), and at one end the small windows are (correct in part) clear, as XC fitted seats in the area at one end of the coach where a luggage rack/toilet once was prior to the XC refurb on most vehicles (except the TGS and 2 of the TFD vehicles across the fleet). Alas only one side at each end is clear on the real thing, and there is no bar half way across on this clear window, but this is forgiveable on the model if we accept the fact that Dapol have given us 4 vehicle types, and that without some minor compromises, we would probably never had had the coaches as it would need 4 different moulds... and the clear windows on the one side can be fixed with a spot of paint...
It's not a perfectly modelled rake of XC coaches due to the above compromises, and I'm sure the purists will make reference to roof mouldings given that no XC HST rake is entirely free of ex-loco hauled conversions as all the TCCs are ex loco-hauled mark 3s, but visually it's a pretty good effort with all vehicle types either represented or in the pipeline (ie TGS), top marks for the efforts in producing the window differences and correctly numbering the different vehicles for the type they represent. My [for now] 2+7 rake looks the part - just missing that pesky TGS now for the full 8-coach setup.
For the record, the vehicle numbers as provided on the coaches are part of set XC02, which bar the TGS, are all ex loco hauled conversions. My vehicles are to be renumbered in main to vehicles from the XC04 rake, which are all 'true' HST vehicles except for the TCC. The exception is that my TSD will be renumbered to the vehicle from XC03 as the window layout on the Dapol TSD is wrong for XC04 and XC05 - the pitfalls of trying to take a snapshot of a small fleet that was cobbled together from lots of different sources and vehicle types to begin with... Even after refurbishment, there are a number of differences across the fleet - different toilet types, seating layouts, CDL panel locations and so on, depending which rake you are looking at and the history of the vehicle in question.