Sorry Faldo, but that website took you in. The etymology, as suggested, may have a semblance of the truth to it, but the phrase 'diamond geezer' as currently used, is the cockney version of Wodehouse's 'good egg'. It just refers to a great bloke - someone you like and trust and would recommend to anyone. It's the sort of phrase you'd hear in Lock, stock and two smoking barrels but not in Four weddings and a funeral.

cheer

the sunshine warrior