With an attack on the Company Car being an attack on Winter, did that inspire Harry to invite Toot and the Za Guard as part of the Garrison of the Castle to make it an official Winter Outpost rather than a personal residence? That way rather than Mab not doing anything to help Harry, she has to defend the attack as an attack on Winter.
In that regard the person who organised the Boom made a rather serious mistake in their timing and is being set up for some major woe. That potentially rules out Marcone and Nameless, neither would be that stupid, not after The Law and the Company Car. The Merlin on the other hand was always my favourite candidate for that, Nick would go for Maggie, too amateurish for for Listen, the Genowskwa would just pull Harry’s head off from under a veil, Mavra and Drakul probably have better things to do with their new recruits, Larry Fowler would sue, Darth Wannabe the previous bomb-maker couldn’t persuade a Gremlin to do anything.
Gremlins are actually a modern folkloric invention from WW1 and the RAF according to Wikipedia, another nod towards the Merlin perhaps? Too recent to be engaged by one of Harry’s enemies in Faerie, like the Redcap.
Is Harry at some point going to trick the Merlin into admitting that he was behind the Boom and point Mab at him?