As to the examples - Somerset Maugham: very popular author. Agatha Christie, even more so. Those books had the relevant phrases in them for a long time.
They also simply indicate that the phrase was well-known and was in use for a long time in the UK.
This specific phrase was one that was quite wide-spread here. I suspect it held on longer here than the US simply because we had fewer people willing and able to kick up a fuss about it.
It’s one of those phrases that people who use it here would almost certainly never even think of it having any kind of racist connotation or be likely to offend anyone. That said they’d probably never actually use it in conversation with a black person - mainly because they almost never speak to a black person.
As I say, I think there were probably plenty of people even in the 80’s who would not only have used the phrase, they would not even have thought of it having any kind of racist connotation and been genuinely offended if you said it had.
If your attitudes and vocabulary were fixed before then (this lady was born in the late 50s’)… and you grew up in and subsequently kept to a certain section of society, you probably don’t really see anything wrong with the phrase at all.
I suspect amongst themselves these people use those terms all the time. See the Bongo-Bongo land thing and far, far too many other examples.
If you want to see similar British attitudes from a more working-class perspective, try a Jim Davidson video. I suspect you probably don’t have to go too far back to find some pretty racist material. He has an OBE.
I believe throwing bananas was/is(?) also popular. Wankers.
