If you read the article it actually says why Streatham High Road is not included.
And that is my point, It just says it's not which makes the whole thing feel redundant...
`In the UK, a "high street" refers to the primary business and commercial street in a town, city or borough, where most of the shops, banks, restaurants, and other businesses are concentrated. It is often considered the main shopping area and social hub of a community.`