Steely
Had the same type of problem (on all the doors), but the bathroom one is dangerous as a number of people have got stuck inside the bathroom, mine got stuck but with no one inside, still had to kick the door down, and jeez are they solidly made if not refined when it came to the lock.
Solution, change all your handles, get handles where the screws go right through and join up both handles (they don't fall off then), as for the bathroom, well i removed the lock completely due to the risk of being stuck in the bathroom, now just have a large bottle of water to put against the door - all bedrooms have a window to get out thru, if u get stuck inside the bathroom u cannot kick ur way out as the door fits flush from the inside, I'm surprised something more serious hasn't happened with someone stuck inside.
I'd recommend endpeg (Steve) on here to sort it for you.