I seem to recall someone did build a P4 BR "508" EMU with working sliding doors and warning lights, so I wonder if that might be a DCC option for the DART......
Paul Berntsen is best known over here for his long collaboration with Andy Mullins, the former proprietor of Branchlines. The kits they jointly developed were a bit hit-and-miss....
^^
This.
An order will be made in the next week or so for a Finney T9 inside motion kit to try to make life a bit easier in respect of crossheads and slidebars......