Gulliver, first you wrote:

What Guest wrote about nobody knowing what Dn3 is, is nonsense. Dublin 3 is the Dublin postal code for Clontarf.

Then you said you did NOT try to say what Dn3 means.

This splits the hair mighty fine.

Riddle me this, then: how was the fact that Dublin 3 is the postal code for Clontarf, relevant to the moniker "Dn3," if you're NOT trying to say that Dn3 means Dublin 3?