All three phrases show up on page 40 of Tinker Tailor Soldier Spy in a single sentence.
"He was waiting for a connect, working a letterbox maybe, or trailing his coat and looking for a pass from a mug like me."
The entire paragraph is:
Once more it was Smiley's turn to receive the heat of Tarr's charm: "So what's it all about, Mr. Smiley? See what I ...
We may never know. Quoting The Atlantic article The Double Life of John le Carré (emphasis mine):
Taking the pen name John le Carré (he doesn’t remember where from),
Cornwell began to write while still working in intelligence.
Maybe to increase the likelihood of getting published initially?
To a previously unknown author, a French-sounding name would lend some cachet.
The semi-opaque world of espionage is intriguing, partly because of the perception that insiders have access to sources of information and other resources, not available to the interested outsider.
Going back ...
TL;DR: Because of the tight secrecy surrounding Operation Witchcraft, there was no such thing as the “Circus view”, only the individual views of the four Circus heads, the “magic circle” as George Smiley calls them. And in each case there could plausibly have been a reason why the flaw in Polyakov’s cover story did not concern them.
The Circus ...