FDW70 seperating waterpump motor from assembly?

Hello,I have a Hotpoint FDW70P,on inspection inside found impellar in pump assy. stiff,freed up impellar retried,still no pumping.
I then took out motor (with assembly) & connected it up on the bench,motor turned briefly then jammed ,switched off,impellar stiff,this happened again and after looking into it seemed the impellar was tightening itself up each time the motor spun. Basically what I want to know the best way to seperate the motor and pump. I remove the 2 screws and turn but it looks there is a circlip but i cant be sure.
Regards Kim