I just saw this in the Radio Times. I missed it the first time, and was so disappointed that the BBC didn't have it on iPlayer for the usual 30 days. (Contractual or licencing obligations I believe)
When it went from small screen grainy black and white, to full screen colour, I had to rewind and watch again, it was incredible.
I found myself pausing it at the end to read all the names and regiments of the men whose voices you hear, and it also made me realise why people wear purple poppies. To my shame, I didn’t really ’get it’ before.