The old radios i've come into contact with here in Ireland didn't even have the wires colour coded so I don't think polarity made a lot of difference. They were wired with twisted pair cables just like the cables used on lamps and the 2-pin schuko style plugs were reversible.
Also as a matter of interest a lot of irish pendant light fittings arn't polarised at all. The cable running from the ceiling rose to the lamp is quite often white twisted pair with so either terminal could be live, not that it matters with the BC connections normally hanging from them. This type of cable seems to hook around the grips inside the rose and the lamp holder much better and also looks nicer.
Most older lamps here too would have used this type of cable right up to the plug. Schuko plugs gripped the cord perfectly however, with BS plugs you often had to tie a knot around the cord grip to ensure it held correctly. There was a double pole press-button switch used in the middle of the cable too. Although im sure in many cases it was single pole.
Very old appliences like vaccum cleaners also used heavy twisted pair in some cases! This was usually inside a cloth cover but the terminals sometimes wern't identified. Just two black cables and a green for earth!
