So I bought new chemicals, I bought the ER/35 remover and gave it another go on my screens (coated with speedball) and the emulsion came off no problem without even a pressure washer (no car wash blues for me!). I also bought some Ulano TZ as Cecilyrhys suggested, I've coated my screens, they are currently drying.
That said I actually just figured out the problem, we were using the Speed Ball screen filler remover not photo emulsion remover. So yeah, duh. Anyway now I'm equipped with the proper gear anyway I think. Can't wait to get some results! Thanks for the help.