Categorically false. "The English people are an ethnic group [...] native to England." [0]

"[White Brits] is an ethnicity classification used for the White population identifying as English..." [1]

The English are the native and indigenous ethnic group to England (London). White Brits are a category that includes the English.

>Of course, separating them out at this point has become difficult.

There is no separation nor difficulty: English people are the indigenous and native group to London.

QED.

[0] https://en.wikipedia.org/wiki/English_people

[1] https://en.wikipedia.org/wiki/White_British#