Help me identify this no-name vintage Omega

This watch belongs to my grandfather.
Bought when he moved to Australia from Italy.
I believe the glass has been broken and replaced once and the glass appears too small as it is hard to see the text down the bottom that says "swiss made".
Its a manual wound watch.
The band is not Omega, I believe it has been lost or broken in the past.
Any info anyone could provide would be greatly appreciated.

To find out more information about this watch you need to bring it to a watch repair shop and have them open the case back. The watch reference will be stamped inside the case back. Take a few photos of this and the movement and Google should be able to give you all the technical details and approximate date of manufacture. Good luck.

Looks like a mid 50s watch by the style