Sellers can exclude delivery to PO boxes, so it seems that when they do eBay's robot falsely recognises your address as a PO box.
You could try asking eBay to change its algorithm to add the word "box" as a condition, but I doubt they will do this just for your benefit. Can you not remove the house name and simply give a street number?
Otherwise all you can do is ask sellers to put you on their exceptions list - assuming that they haven't also blocked messages from blocked addresses.