Irish town you might have been in first? Oddly, no (5)
I believe the answer is:
ennis
'irish town' is the definition.
(I've seen this before)
'been in first? oddly no' is the wordplay.
'oddly no' indicates alternate letters (letters in odd-numbered positions removed).
'been'+'in'+'first'='beeninfirst'
The alternating letters of 'beeninfirst' are 'ENNIS'.
'you might have' is the link.
(Other definitions for ennis that I've seen before include "Poster girl" , "place of Clare" , "County town of Co Clare, Ireland" , "Southern Irish town" , "our potential 1/4 Across [GOLD MEDALLIST] in 2012" .)