I worked in the coal mines for a while in my younger days and in the south yorkshire pits a bevin boy was always regarded as something less than a miner, even 20 or so tears after the war.
Now because coal was a nessesity for the war effort, mr bevin brought about an act whereby a concientious objector was able to contribute to the country by working in one of the industries deemed nessesary to the country.
many of these boys were genuine objectors but the stigma of being a bevin boy held for many many years.
Bevin Boys were not conscientious objectors, and vice versa. The Bevin Boy scheme was, indeed, instituted by Ernest Bevin, Minister of Labour and National Service, in 1943, as a means of ensuring an adequate supply of miners to hew coal essential for both industry and heating homes. It operated by a civil servant each week drawing a paper out of a hat containing 10 pieces numbered 0-9. That week all men due for call-up whose National Service number ended with the chosen digit were compulsorily diverted from the armed forces into mining (subject to exceptions for the medically unfit and essential workers in other industries). Men already in mining were not allowed to leave (except for health or age reasons), but that did not make them Bevin Boys, nor were they ever so called.
Some men recognised as conscientious objectors were given mining as one of a range of conditions of exemption from military service, but that also did not make them Bevin Boys.
The scheme continued for a couple of years after the end of the war, and the designated men continued to be known as Bevin Boys, although Ernest Bevin had moved on to be Foreign Secretary. The scheme had nothing whatsoever to do with Aneurin Bevan, who was a backbench MP in WW2, and there never were any Bevan Boys, despite the confusing title allocated to this thread. There was no-one of any relevance named Beven, and there were never any Beven Boys.