The man seemed all kinds of formal, so Miguel didn't bother asking how he could shorten 'Fitzwilliam'. "Good to meet you, Mr Darcy. There are a lot of Miss Sullys here by the way, but no, I'm not related to them." Fake-married to a Sully didn't count.
He ran a still-unsteady hand through his hair and took another couple of deep breaths after that. "Where are you from, if you don't mind me asking?"