Beer in Dublin Airport (The Pre-fab Terminal)

While waiting for a flight out of Dublin yesterday I decided to have a drink. I was in the A block that comprises of gates A64 - A71. It is the one with the long walk along the Pre Fabricated buildings and I think only Ryanair fly in and out of this section.
My problem was I ordered a pint of beer (cost €4.85) and received a plastic container which was not a pint and I would hazard a guess that it was not even two thrids of a pint.
My gripe is that surely for €4.85 I should get a full pint in a PINT GLASS. Also, under customs and excise (weighs and measures) regulations surely the glasses have to have a customs and excise stamp to ensure that people are getting the correct measure. The plastic containers did not have this stamp. This I believe is illegal. I asked the barman about it and received a blank look followed by a response "I only work here" he then turned to the other barman, laughed and said "some people".
Also, I didn't see a price list (required by law) but I may have missed it.

Anyone know what the customs and excise regulations are for this?

Look at the section . Different rules may apply to departure areas of airports, e.g. I think they're still open on a Good Friday.

Good point. If you asked for a pint of beer but not given a pint of beer that you were "ripped off". Clubman might add that you should have handed back your two third pint and not proceeded with the transaction or drunk the two thirds and then went back and asked for the remainder. Why not follow it up with the revenue and the bar concerned. Their price list should display the cost of a pint and your drink should be priced pro rata.

I do not know if the law has changed (probably not) but when I was a publican you were obliged by law to use stamped glasses.
The Gardai have a department called "weights and measures" and they would periodically check and you could be prosecuted if you had unstamped glasses.
Most, if not all ignored this law as those glasses cost more but they still would not serve a small measure.
Serving a small measure should be punished using every law possible. Make a complaint.