Kurt, don’t want to burst your bubble but it’s almost impossible to find a watch for less than £1000 that would be an investment watch. Reckon you would have to travel the antique markets and hope to get lucky. I have a mate, used to be a collector, who reckoned anything less than $10k and you might as well buy that Casio you always liked... he was a watch snob of note.
If you have no interest in the watch I reckon there would be a lot more growth in pure equity shares or some other investments that would deliver a better return.
Edit: I see you’ve been answered very well above. Seems the 10k bench is the standard minimum investment.