Hi Ninsaga,
Was just in my local postoffice in Co. Cork today asking the very same question! My house has two different names - one naff one which is on the deeds and an even more naffer and depressing one which the previous owners came up with! So I get mail to both names as the postman goes back a few years and is familiar with the setup.
Anyhow, you could change the name of the house on the deeds which could be costly and timeconsuming. Or, and this is what I am going to do is just change the name and inform the postman of the new change- the local postmaster had no problem with this. Course I'll then ensure that all mail is sent to my new address so as to not entirely confuse the poor man. The only trouble that you may come up against is if you were going to sell your house in the future for land registry searches where they would be looking for the name on the deeds...but I'm guessing on that one.
Regards,
C71 (who can't wait to change the name to get a reference to Louth in Co. Cork!!!)