Numbered Bands WW2

[Padre]

I have had this pair of bands for quite some years since getting them with some ATC stuff. I have never been able to identify them but have seen other identical examples (aside from the number) here and there.

The black example is an armband, with a loop that presumably goes over the shoulder to stop it slipping down the arm, while the blue one is a tube, open at each end which makes me think it was worn on a belt.

My only thought is something like the National Service Rally of 1939 where the various home front organisations were lined up in numbered areas, wearing a badge with the area number on. Outside that some sort of sports number?

If anyone has any information I'd appreciate it, then I can finally put them in the collection or not!

Thanks