Group gym sessions for boys (14 years old)

[spmoce]

Hello, does anyone know of any group gym sessions for boys (14 year olds) in the area? Perhaps a personal trainer who would be up for working with a few boys at once (or one who’s already doing so)? We are members at Dulwich Leisure but my son would like to workout with a group rather than with a trainer 1-2-1. Any suggestions, please let me know.