Mystery Photograph - Boys Brigade/ St John's/ Colliery Band or ??

This studio photograph of a smart looking young man named Charles Gunn is a mystery to Gill the owner.

Charles was known to be  living in Argle Street  Mansfield Woodhouse from 1916.  On the back of the photo  is written ‘Boys Brigade.’  However it is questionable if this is the uniform of the Boys Brigade.

Charles was a Private in the West Yorks Regiments but it does not appear to be a military uniform, he was discharged due to being wounded in August 1918   He is wearing two medals, are these from his army service?

There’s a possibility the uniform could be linked  to music as it is believed he played the bugle.

Very little about Charles as he died in 1930.