The main thing is coupling lock, so I run everything anti clockwise and use stock with only the hook fitted on the interior side...
Agreed. I centred the coupling hook at one end of my stock and modified the other to pivot a clear plastic flap, which gives the Hornby coupling a genuine delayed-action effect (can push a wagon to anywhere on a siding and leave it there.)
As a side benefit it also makes the single hook less likely to "bounce" uncoupled by accident.
Loco is a Triang "Nellie" style body, with a Bachmann Junior 0-6-0 chassis converted to 0-4-2.