I've heard of these coming up for sale once in a blue moon but does anyone have any info on them?

I have one. What do you want to know about them?

It depends on what you mean.  Are you talking about the Irish Contract no4 mk2 Enfields, or are you talking about a Royal Irish Constabulary SMLE?

There are a variety of different Irish Enfield rifles. The so-called "Irish Contract" No. 4 Mk. 2s were mostly not delivered to Ireland.

Irish SMLEs have a number of identifying marks. The stacked "FF in a circle" Fianna Fail mark is one of them, and generally appears on the barrel shank and or knox form. Irish Mk. Is and Mk. I half-converts can be easily identified by their restamped serials with specific prefixes (ER, CR, and G).

I'm on the lookout for one of those ER, CR, or G rifles, I'd love to add one to my collection....

Royal Irish Constabulary SMLE

They're a much more rare animal.  The RIC carbines are converted Lee-Enfield cavalry carbines (technically not an SMLE), all made prior to 1904 and converted between 1904 and the beginning of WWI.  Finding one that is complete and correct is not particularly common.

They should have a short, six round magazine.  The royal cypher will be on the left side of the butt socket, rather than the right, and the rifle will be marked beneath the cypher as a Lee-Enfield carbine (LEC I or I*).

Lots of good pictures here.