"I work full time so can't home educate, I can't afford private. My son is on waiting lists but very low down all of them, I'm assuming this will change now he has no place at all."
PoppyPia, I'm sorry to tell you that it doesn't work like that.
All rejecting the allocated place has achieved, is ensuring that your DS has nowhere to go in September.
The admissions criteria for each school is clear, legally binding and cannot be circumnavigated by rejecting a place.
Your DS will not go up the list on his waiting list schools because you have rejected the place. He will remain where he is on the list unless someone gets allocated a place at the school (so he will go up the list by one place) or someone moves into the area, closer to the school than you (so he will move down the list by one place), etc.
The LA now have no obligation to find you a place for your DS. Of course, if there is a school with places, you're entitled to a place, but given that your allocated school was so far away, it's pretty certain that there are no closer schools with places.