I've never been to Staines, but always assumed the Ali G joke was that he was a middle class white kid who thought he was a black kid from South Central LA.
From what I've heard it's convenient but not the best TV around. And you'd need very fast and very reliable internet to take advantage of it.
https://www.wired.co.uk/article/sky-glass-tv-review
Yeah, I often hear people talking about St Pauls/Easton like it's still 1995. Both those areas are gentrifying at a huge rate and normal people are completely priced out.