SpookyCharlotte - If the problems regarding access ever came in front of a family law judge in the court, I can GUARANTEE you that the judge would INSIST that the father would have to find the money to transport himself to and from the access and ALSO that the father HAS to provide ANYTHING the child will need for that access visit - clothes, food, nappies, formula milk if FF, honestly, I've been there twice. While I can (truly) understand why you're trying so hard to make him have contact (I had to do the same sort of thing at first with DS1's dad), it will NOT help a bad father to become a better father.
When I laid down the law with DS1's dad (he was about 18mo at the time, and I'd just had DS2 with my new partner, so being unable to run around after ex like a skivvy), he stopped seeing DS1 for 6 months. He then took me to court for access ( didn't remember ME stopping it lol). Judge made him (out of HIS jsa) pay his transport, and told me not to provide ANYTHING. Due to 6 months of no contact etc, we started off with supervised in a contact centre progressed to unsupervised day visits, then overnights.
Where we are now with access, now DS1 is almost 7yo : Ex has become a brilliant father, pays for half of all school trips without prompting, buys clothes, school uniform, shoes. He has DS1 overnight EVERY wednesday, every other weekend, half of ALL school holidays, and has genuinely turned into a decent human being. (god, did I just say that!). I can now see the Judge's point. I was enabling his crappy behaviour by allowing the situation to continue like that, and when ex was made to step up to the plate, he did.
I'd say do it the way you had originally arranged this once, as a last time, despite your ex's general twuntishness. Then make it plain that if other fathers can manage to catch buses etc to see their DC, he'll do it if he really wants to. He is to pay his own transport, and provide anything your dc's may need for the time he is with them. Don't have access in your house - christ, DS1's dad when he got serious used to find the money for soft play out of his jsa - And that he is to turn up on time. I strongly suggest putting your foot down about HOW the contact takes place, but NOT about stopping the contact. Good Luck.