Vintage computer - a hand held paper tape punch

I saw this at an antique fair in Manchester and bought it.
I now own 2.
I've only ever seen 2.
My other one is different to this but both were built to last for a long long time.

It would be used to punch holes into paper tape that would then be fed into a computer.
Probably 1970s although my other one was used in anger in the early 1980s when I worked forthe DHSS.

I wasn't going to buy this until I realised that the 'loose lever on the right' was in fact a guillotine