Hotpoint Aquarius 1100 when draining overflows from the J pipe (U pipe?)?

When our Hotpoint Aquarius 1100 drains water which (occurs approx 5 times during 1 cycle, have counted!) we have to keep stop/starting the on/off switch approx 3 times, as our pipe (J bend? U bend?) cant seem to cope with the speed of water being expelled so therefore overflows. We are positive that this isnt due to a blockage in our pipes as everything else is fine. Any help would be REALLY appreciated as i'm wasting my life stood in front of my Washer/Dryer!! Thanks