ADSL telcos all require a phone line and if one ADSL telco is saying no, then you shouldn’t go with any of them as it all comes down the same pipe or copper from your local exchange…. My humble recommendation would be go wireless if any of the ADSL telcos say no. Some parts of towns have better copper and are connected closer to the phone exchange in your area, if you’re wondering why? Then you’re looking at power loss of frequencies down a copper line.
dslreports has done a break down of this here http://www.dslreports.com/faq/4676
but if your looking for actual Irish data here is the best I could find.
http://www.eircom.net/efibreinfo/map/
here’s is Eircom talking about it below, you can’t really beat physics no matter how hard you try!
http://www.finfacts.ie/irishfinancenews/article_1016178.shtml
or if you want to help map what ADSL is in the area