Cones became commonplace from late 1960s. There were black base ones, types moulded from black rubber with a plastic sleeve that formed the red and white bit that slipped over the top. Mostly though before 1986 cones were still one piece plastic weighted with a sandbag. Best ones I use on my layout which I think are accurate for any period are the ‘modelscene’ ones. Easy too to assemble.
The oil lamps were yellow and red into the mid seventies. Red was phased out due to yellow becoming more visible and finally due to health and safety and cost of oil lamps . They disappeared completely by the early 1980s. Nobody as far as I know makes them in oo; only nearest possibility is somebody (can’t remember who) makes red GWR tail lamps. These possibly could be modified. Flashing yellow battery lamps were introduced in 1966 by Dorman. These were often on tripods. But again these would be a pig to model.
Barriers up until the mid 70s could still be made of wood. ‘Scalemodel scenery’ do a great set of these barriers if you’re modelling I’d say pre 1977. 1977 to late 80s many barriers were fitted to cones with adaptors or big heavy red barrier posts were used manufactured by a company called Glasdon in Blackpool. The one section laser cut barriers you can buy everywhere now only came in from the early 2000s and these would be incorrect for a layout prior to 1999.
And anybody whose a certain age will remember the old striped GPO tent used by BT and the gpo!
I’ve made one for my layout. Bachmann do one in a set but it’s expensive and the figures that come with it are too modern for my layout. There’s plenty of pics online you can get templates from.