The library can only supply a copy if the original is on micro-film. Unfortunately, as far as I know, the SWDN is still hard copy. However, your friend could take a photograph of the original.
You might consider ringing the library (029-20382116, ask for Local Studies) to check if that is still the case. Also, you could ask them to check that there is a photo of your great-uncle in the SWDN. Since you have a precise date, they might be willing to do so, if you tell them you live outside the area and don't want to make a wasted journey (though no journey to Cardiff is ever wasted!).
thank you for being patient and replying to my queries. I'll phone the library.
If you are still researching Cardiff lads can I mention another great-uncle -Thomas Powditch of the 13th. Middlesex Regiment? He was killed at Trones Wood on August 18th 1916. He lived at 21, Swansea Street
with his family. He enlisted at Paddington because he was a steward on the G.W.R. apparently a really lovely person. I do have photographs of him, so I'm lucky. Thanks, Pam.