There's no drink restriction at the DUB lounge. It's quite similar to the T1 lounge, which is the UK and Ireland lounge near to the probable departure gate. I assume this trip is before DUB services move to T5 at the end of October.

The DUB lounge is above the security check in area. From security there is a sign to the DAA lounge, it doesn't specifically mention BA until you get upstairs to the reception area. It has wine, beer and spirit on a self pour buffet. To nibble there are biscuits, cake, savoury snacks, bread and butter, soup. Possibly slightly better food options than T1, slightly worse drink options. The lounge is split over two areas, but the food and drink are replicated in both sections.

I'd pop down to Dublin if you have 5 hours there, if you are avoiding rush hour you can be in central Dublin well within an hour of arrival on the competing bus services. The lounge would get a bit boring for that length of time, after an hour or two the novelty will have worn off.