What an incredible find! Does anyone know where it has all got to?
I would agree that it is 2 foot gauge, based on the photo of the Ruston. Frame extensions would be needed if it was any other gauge.
The lever frame was a bit of a surprise. It is a BR standard 1943 frame, an evolution of something first designed by the Midland Railway. Mechanical locking between the levers is in the flat tray extension behind the levers, operated by the lever catch handles. Some of the lever colours make sense, the blue/black levers would ordinarily be for points worked by a motor or an economic facing point lock. The yellow lever would be for a distant signal and the red levers for stop signals. There seem to be way too many white bands around the levers as these indicate a signal released by a "line clear" from the signalbox ahead. Some of the other lever colouring is a bit weird for want of a better term. Goodness knows what the red buttons are for, but I would be amazed if there were any electrical controls on this lot. I do wonder how well the lever frame fared in the great outdoors as this type was only ever intended to be used in a proper signalbox.
I really must stop boring you all with signalling anorak-ness now as my day job is taking over the hobby!