If he was doing his national service that would put him as being between say 18 and 21 in 1963, national service had ended for intake but in 1963 there were some recruits still due for discharge.
Based on that theory, looking thru the births in England and Wales for a Samuel Edwards between 1942 and 1945 doesn;t take too long, and infact there are only 4 Samuel Edwards births registered between those years.
The index gives the childs name and surname, the mothers maiden name and the registration district and reference
I use the term Q1 to mean the 1st quarter of a year so births registered jan - mar are in the 1st quarter and so on
The entries I have found are:
Q1 1943 Samuel P.Edwards Mother's maiden surname Williams registered at Hollywell ref 11b 173
Q3 1943 Samuel Edwards Mothers maiden name Condliffe registered Stoke 6b 276
Q1 1945 Samuel T Edwards Mothers maiden name Barton registered Anglesey Ref 11b 894
Q4 1945 Samuel A. Edwards Mothers maiden name Waterhouse registered Birkenhead 8a 880.
Now that is a long shot, but having looked at the Edwards registrations for 16 quarters over those 4 years, Samuel is by ni means a common christian name, this is good news for you as it will mean you will probably have less options.
But if I am correct in that he was one of the tailend National Service recruits, in the 35 Engineers at Maidstone, then he is likely to have been bweteen those ages.
Do you know if he was Welsh at all?