Perhaps lestrade on cello?

Perhaps lestrade on cello?

In my, I don’t know, alternate universe, Lestrade, Molly, Sherlock and John form a string quartet. Although sometimes Molly is replaced by Mycroft.

Violins- Mycroft and Sherlock (they’d have a right old time arguing over who should play first and second)
Viola- John, of course
Cello- Lestrade
Piano (for trio/quintet)- Molly