whats the difference between these and Battlemages?
Mostly lore, check the differences between the classes in Daggerfall, Morrowind and Oblivion (skills and descriptions). In Morrowind besides the magic skills the battlemage had heavy armor and possibly two handed weapons (blade, axe, no block skill) and the spellsword medium armor and block which indicates they are supposed to wear a shield and use one handed weapons (blade, blunt, fits with their legion background in Morrowind)
In Oblivion Battlemage's had no armor and Spellswords had heavy armor