Dry-fitting parts is always a good idea. Put things together without glue and you'll spot potential issues that won't be any easier to deal with when the adhesive is flowing and getting all over your hands.
As you can see, there is a part fit issue with the Cravens DMU floor. Basically, it's too long.
To be fair, this is mentioned in the instructions, but is a bit of a surprise when you see just how bad the situation is. The solution was to lop 2mm off each end of the floor and then thin the ends slightly s they fitted in the pockets in the whitemetal bits. 3mm would probably have been enough but I'm better at measuring whole mm, and the extra 1/2mm at each end wasn't going to be an issue. A bit of wiggle room is welcome.
First though, the interior. On a parcels unit, this isn't much, but I feel that something in the cab is a good idea and had picked up a couple of mouldings from Replica Railways. After a little trimming, they will fit in behind the cab fronts OK.
More importantly, they will fit through the holes in the floor the power bogie occupies. I'll need to fit them after the glazing goes in, and that has to be done after painting. There's a fair bit of thinking ahead required with this kit.
Ayway, floor trimmed and fitted with epoxy glue and I have a model that starts to look like a DMU.