What model is this Smiths?

Today I'm wearing my Smiths watch. It is vintage [I would guess: late 1960s], bought 2nd hand on ebay. The watch has no indication on it of a model name or number. So, what is that model?

Lookswise, I have seen very similar models with the names Astral, Empire, and Imperial:

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But: all of these also have that model name on the dial.

I'd like to know so that I can include that watch in my Watchcrunch Watch Collection without having to make up a model name.

Hey, it does look like a late model of the empire. I think it's early 70s , very early.

I don鈥檛 know but looks awesome