A very offbeat example in Smiley's People, when Toby Estherhase refuses to sell Smiley an expensive but fake Degas statuette. It's both a warning about the dangers of Smiley's current project and an expression of genuine loyalty.
In The Honourable Schoolboy, Westerby breaks Guillam's arm. This doesn't stop Guillam from intercepting Martello, who attempts to threaten Smiley. It's noted that even with a broken arm, Guillam could still overpower Martello when Smiley is concerned.
In Smiley's People, Guillam receives a tense call from his wife and immediately fears that she's being held hostage. He chucks the most important key of the office at his assistant, Drives Like Crazy to get to his apartment, and then tries to attack the kidnappers to save her. Which means that he almost breaks the arm of poor old Smiley.