Once I'd worked out that I'd forgotten to gap a set of copperclad sleepers, and it was this that was causing the controller to go ping, the testing of the two main boards of Llynford could continue with this ancient ( father-in-law's) Airfix Cl 31. So worn that it actually shakes in one direction. I have to admit that the ease of running with the weight of 4mm standard (?) gauge is refreshing.
Dead-end isolation gap to wire-up and that's the technical bit more or less done.