As an Irish child reader, I never really grasped how Thalia could sound like 'Failure', even in a noisy train corridor. It seemed somewhat more probable when I had a child in London, many of whose friends, when small, pronounced 'th' as 'f'.
Even so, I just think AF couldn't resist the meetcute punchline, which establishes Lawrie as tactless but funny, and the Marlowverse as one in which the character in whose POV we chiefly are prefers boys to girls, despite being a girl.
(Doesn't Tim in that initial meeting scene on the train also grin at Nicola and say she likes the navy 'better than anything'? Does this ever come up again? Why would Tim have any particular feelings about the navy?)
Talking of AF meetcutes, could there be a worse one (though brilliantly written!) than when Nick meets Patrick up a tree freeing a trapped Jael (or is it Regina?) in Falconer's Lure? He's so foully rude to her, scoffs at her not knowing the precise vocabulary of hawking, and couldn't be less interested in her being quite badly cut up by his bird.
I like when Nicola and Esther meet when Sprog flies off from the train in the middle of Esther's abortive runaway attempt and walk to school together (though Esther is much more snubbing and less timid and well-meaning than she is later on?)
I always find the one at the start of the Nick/Miranda friendship slightly puzzling, and I like Miranda. OK, we're told that they'd gradually been growing friendlier since the Kitchen and Jumble days, but suddenly they're holding hands and swinging their joined hands together running down a path at school? It always sounds much younger than their age at that point.