From Al Khail road heading towards SZR ( Junction 4 MOE) , it is the first IMMEDIATE turn RIGHT- follow road round and it is on the left hand side..sorry can't remember name ..not sure if it is for women...rugby boys used to go there.
Urban Energy fitness runs kickboxing class outdoors in Umm Suquiem park and Barsha Park. it's not purely boxing as it involves knee and leg kicks but it may be of interest ?