While you are on the site, in your browser find and click "Add to Home Screen" A CGN beaver app icon will then be created to your phone that is directly link to the site.
Note: This feature may not be available in some browsers.
I am afraid you got yourself a nice little 18 gauge shotgun instead of a 303 Enfield ...
Therefore I will save you a lot of trouble and take it of you hands for $50.00...
Cheers
My money is that the CE18GA is the drawing or part number for the complete rifle. The A likely stands for Assembly.
Most of the parts on the 50s Enfields had CE type numbers on them. Later these numbers were replaced once the British adopted the NATO stock number system.