Can you share why you and your son were not living together? for example my former friend left her partner to live with om, and left her son to take him with her later when she got settled...
The other case I know of, was someone who worked with a family member, she was not from this country and worked full time, her husband left for ow who did not work, not sure how but he and ow got the house and the son and she got contacat and had to pay maintenance, she was not great at English as she was from abroad, her hubby and ow were English...
Both cases were of boys of 10 years, not sure if he said it to make his mum feel better, but former freinds son told her his dad promised him things if he said he would stay with him to cafcass and never followed through, however he never once asked former friend to live with her and he always put his relationship with his dad first, so not sure if that was true or to make her feel better about things...
Why the hell did your barrister not get fixed contact, they don't sound that good to me if it has been left open and you and your ex don't communicate well, you may need to go back and get a defined contact order if that does not work out well...