That would be fitting: historically, when Leith and Edinburgh were separate, it was on the boundary. When the two had different licensing laws, one side of the pub would close earlier and people had to move over to the other side. But an EH7 postcode would need to go with a Crighton Place address, the EH6 postcode is the only one that makes sense for a Leith Walk address. Therefore I'm inclined to agree with FHRS here...