The correct identification can be found here:
https://www.queenscollege.org.uk/upl...utumn-2018.pdf
The cap badge is that of the short-lived cadet corps that existed in WW1 at Queen's College Taunton. The school does not have a CCF and surprisingly unlike King's and Taunton schools which are in the same town did not get OTC status. It is equally prestigious as its counterparts in the town but does have a Quaker tradition so i wonder if the undercurrent of pacifism saw a lack of enthusiasm from the Teachers in the military: hence the short lived cadet corps.
Not Welsh and not a band. Bosleys' expert does need to sharpen up his act!