I've had a change of plan with what to do next on the carriage.
Instead of adding the vacuum pipes I got out the soldering iron and added the couplings to the bogies the other night.
We have standardised with the fold-up brass Greenwich couplings on our rolling stock and they are the default option for any stock I am building for a client too.
Among their advantage is that it is very simple to re-position them, you just apply the hot tip of the iron and melt them off and fix them back in place.
I don't know what the client has planned for his Disco Car yet, and whether it will ever run on a layout as part of a train, so it is hard to know whether to set them in a close-coupled position or not.
So I have played safe and set them very generously so to reduce the chances of things like the corridor connections or the vac pipes locking with those on any other stock it is coupled do.
It's possible, after all, that it may make a guest appearance on Dduallt or Bron Hebog one day.