H from H,
I would suggest that you don't bother with National Flight Centre. My own personal experience of them was very poor (over a period of about 6 months). From speaking to others, my experience is the norm, rather than the exception.
There any only two place in Dublin to fly powered a/c. Weston & Dublin Airport.
Weston is by far, the base for GA in Dublin. I would that you try Sky Trace in Weston. They operate a Robin & an Arrow as far as I know. I haven't flown with them, but have heard nothing but good reports about them.
If you have a ppl and will be in Dublin on a long term basis, you could checkout the clubs in Dublin airport. They do have a joing fee & monthly subscriptions, so not suited to a short stay.
The clubs in Dublin are :
Dublin Flyers (operate a PA28 & a P28R)
http://www.geocities.com/dubflyer
Airport Flying Club (operate two C172's )
http://www.airportflyingclub.com/
Leinster Flying Club (operate a C172 I think)
http://www.leinsteraeroclub.com/index.php
Unfortunately I don't have a website for Sky Trace in Weston but their phone number is 01-6280144 (00-353-1-6280144 if calling from uk)
As I said I wouldn't recommond NFC, but if you're on temporarly here, and want to rent a C150/172 then you may have little choice. Their phone number is 01 6282930.
Regards
dp
BRL- I've no connection with any of these (other than being a member of one of the Dublin Airport ones), and I've mentioned all the ones that I know of!