The way I heard it was that the photo was taken by Bert Hardy outside the Eton-Harrow cricket match at Lords in 1937. The posh boys were - it was claimed - from Harrow, not Eton, and their names were Peter Wagner (left) and Thomas Dyson (right).
Dyson died in India whilst still a pupil but Wagner served as a Signals Lieutenant during the war and lived until 1984. The local urchins were George Young, Jack Catlin and George Salmon. The first two of these were certainly still alive in 1993, aged 68 and 67, at which time ‘The Times' published an article about them. Oddly enough perhaps, they had both become Conservative Party supporters!
(Take my advice and do not search any further for this on the Internet! You'll be astonished what asking for photographs of schoolboys throws up. I'm just worried now that - if I ever have to get my computer repaired - I'll finish up banged up like Gary Glitter!)
If I have the name of the photographer wrong, as Sophie's answer suggests, then blame The Times! The rest of the information I got via research.