Below is a picture of the Pemara printing of the 55c Butterwort roll issue. As can be seen the perforations are markedly different to the other printers.

The stamps where the text on the right of the stamp ends level with the flowers stem are printed by Ashton-Potter. This can be seen on my posting of the items found on
ebay.
The March 2011 Ashton-Potter roll printing was issued with no box, just the roll of stamps in a cellophane wrapper. All previous roll issues came in boxes.
At least there are only 2 different booklets, one issued 20th April 2007, thought to be by SEP Print, which has a full size stamp, the other, issued 6th November 2009, by Ashton Potter, this has the small size, 20 x 24mm, stamp.
On looking through old issues of the AnPost 'Collector' magazine and the Eire Philatelic Association 'Revealer' publication I believe that the printers of the self-adhesive N & 55c Butterwort stamps were:
1st March 2007, 10 x N Rate Booklet, (AnPost ref 07DBK1).
SEP Print. Perf 11 x 11 1/4. (Revealer Summer 2008, page 4-5).
Booklet contained 5 x Butterwort and 5 x Blue-eyed Grass stamps.
1st March 2007, 100 x N Rate Roll in box, (AnPost ref 07DSASB1).
Sprintpak - SEP Sprint. Perf 11 x 11 1/4 . (Revealer Summer 2008, page 4-5).
This stamp alternated with the 55c Blue-eyed Grass on the roll.
20th April 2007, 10 x 55c Butterwort Booklet, (AnPost ref 07DBK3).
?SEP Print? Perf 11 1/4 x 11 1/4. (Revealer Summer 2008, page 4-5).
Printer not confirmed.
20th April 2007, 100 x 55c Butterwort Roll in box, (AnPost ref n/k).
Sprintpak - Pemara. Perf 12 3/4 x 12 3/4 . (Revealer Summer 2008, page 4-5)
Name on right side ends short of flower stem.
Sept 2007, 100 x 55c Butterwort Roll in box, (AnPost ref n/k).
Sprintpak - SEP SPrint. Perf 11 x 11 1/4, (Revealer Summer 2008, page 4-5)
Name on right side ends short of flower stem.
Oct 2008, 100 x 55c Butterwort Roll in box, (AnPost ref n/k).
Sprintpak – Energi Print. Perf 11 1/4 x 11 1/2. Narrow Phosphor frame. (Revealer Spring 2009, page 67)
Jan 2009, 100 x 55c Butterwort Roll in box, (AnPost ref n/k).
Ashton Potter. Perf 11 1/4 x 11 1/2. (Revealer Spring 2009, page 66-67)
6th Nov 2009, 10 x 55c Butterwort Booklet, (AnPost ref n/k, SG SB152).
Ashton Potter. Perf 14 x 14 1/4. Small size 20x24 mm
Mar 2011, 100 x 55c Butterwort Roll, (AnPost ref 11DSASR). No box.
Ashton Potter. (Collector 2011-01 page 10 & Last Chance page)
Name on right side ends level with flower stem.
Hopefully the above is of help. If anyone can find any other information that confirms or amends any of the above I will not be offended. Since it is several years since these stamps were issued, and there was not really any information put out by AnPost at the time it is easy to make mistakes.
I just wish that the 5th Definitive series, 'Birds of Ireland' were as easy as this set.