So Sherlock's just a chip off the old block in a way?

Pretty much. I have to admit the lure of writing Siger is essentially being able to write Sherlock in love and Sherlock as a dad, two things I would never attempt because they'd be so out of character. I've actually had to correct myself a few times for Mycroft's story. I kept writing 'Sherlock' instead of 'Siger'.

We all know 'stop being stupid' is Holmesian for 'I love you', anyway. :p