I propose you arrange for a big bloke friend or relative to be visiting when your ex is next due.
Have all of his stuff (that isn't worth selling) piled up outside your front door. Make it clear that if he wants it stored he can make his own arrangements. Bolt the front door and make yourself and friend a nice cup of tea.
I guarantee that any urgent need to see child (and push your buttons) will evaporate on sight of big bloke.
As for no transport blah blah, stop falling for that crap, you are not his mother, he is an adult, he can call a cab, have a storage trailer brought or phone a friend with a car. No talk of money or selling stuff just "here is your stuff, this is not a storage unit, bye", any other questions can be answered by a shrug or at most "dunno".
Stop believing you are responsible for him, he is your common or garden variety cocklodger - flush him out. Your only concern here is your child, sadly you can't affect his concern for the same child. It sucks but you'll get used to it and things will get much easier once you feel in charge of your own life again.
The difference between "having a legal right" to something (as you put it) and getting it is realistically finding a sympathetic court and bothering your backside to go to court, now ask yourself how likely that is and get his crap packed up and out of your life.