Need directional arrows to stop people cutting over

I understand that the queue is horrendous at this junction but with no traffic lights controlling the traffic on this slip road everyone seems to think its ok to use the left hand lane to turn right. This then causes dangerous situations. If we can't have lights can we at least have road markings instructing people that the left hand lane turns left to Great Yorkshire Way or straight back on to the M18, and the Right hand lane turns right. Although Lights would also be great. Thank you.