Tyres.... sorry Tires question

Not sure regarding the wheel size per se unless some can tell me what I need to measure... slightly complicated by the fact the car isn't with me at the moment. I've looked at the spare and found ... refer to the photo... Build date wise looked at the documents I got with it when I bought it. It was built August 1972 for the 73 model year.
No one does those make of tyres/tires in the UK.

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Vin and title makes it a '73 model