  The odd parity gravitational Quasi-Normal Mode spectrum of black holes with
non-trivial scalar hair in Horndeski gravity is investigated. We study `almost'
Schwarzschild black holes such that any modifications to the spacetime geometry
(including the scalar field profile) are treated as small quantities. A
modified Regge-Wheeler style equation for the odd parity gravitational degree
of freedom is presented to quadratic order in the scalar hair and spacetime
modifications, and a parameterisation of the modified Quasi-Normal Mode
spectrum is calculated. In addition, statistical error estimates for the new
hairy parameters of the black hole and scalar field are given.
