Not as easy to find evening group classes without going to a Uni. Private classes are easier to find at night.
This place has some right now ShuoHao Language Center
Also the schools don’t always advertise well. Even after checking websites I always end up dropping in to get the real scoop.
Check TMI, TCA, TMC, TLI all located generally in the same area near Roosevelt Road.
All these school teach in English and Chinese. Less English as you progress of course.