Here's a photo of each design.
The rotary disc signal first (Leicester c1894), then a 'Frost' (Nottingham 1960's), then an 'Acfield' location and date not known but thought to be 1960's.
Thomas To help with the signal lamps here are two photos which may help you. First Leicester c1894 (widening and rebuilding of Leicester station). The second is a lovely bracket signal at Tuffley Junction, note the different signal lamps.
Looking at the 'Frost' ground signal photo I realise since posting it that it is slightly misleading in that it shows the improved arm variant whereas the original design didn't have the white half circle attached to each arm and had a smaller diameter red spectacle glass, see photo below at Saffron Lane Junction taken in the late 1950's.