It's definitely interesting to read a wide range of responses (mostly critical!), for which many thanks to all. I certainly don't feel chastised (
) and have learned a few things from this thread.
It is notable that most posters are taking a broad view of the circumstances vs the much more narrow matter of whether BA were justified in not checking me in despite having a valid ticket, and presenting a valid passport at check-in.
Also, whereas many people are focusing on (as they see it) me trying to make money when I had screwed up, in fact I was simply asking for advice from others based on their knowledge and experience.
Tobias - final destination was LHR. BA state on their website re ID requirements:
https://www.britishairways.com/en-gb...-visas-and-api
For flights between the UK and Republic of Ireland
If you are a citizen of the UK or Republic of Ireland who was born in that country you do not need a passport to travel between the two countries but you do require some form of photographic identification, such as a driving licence.
All other travelers require a valid passport to travel between the two countries.
I was very interested to read another poster copying an extract from Aer Lingus's website, in which they don't require photo ID for children younger than 16. I wonder why BA have adopted their more stringent requirements?