I found a website where someone managed to unscrew the top cup part and there actually were hallmarks underneath there but they had been deliberately obscured, so at least the cup is solid sterling silver, and the rest of the body might be solid sterling silver as well (not sure, still researching). ::::::
"Made in 1944 in England, a seemingly ordinary full size silver plated chalice with no real salvage value, until the cup is unscrewed revealing the silver marks. The story is that these chalices were manufactured this way quite deliberately to stop the silver component funding the German war effort if any chalice was to be captured and confiscated. Whether it is true or not is another matter, but it's a good story."
:: Right, so these Chalices and Patens (if you can find an example) might have been deliberately made to obscure the fact that they were solid sterling silver, and since they were always used in a wartime setting, you wouldn't want the enemy to steal this and fund their war effort against the British Army. :::::