Ok thanks for the positive responses and guidance, mostly*.
SITREP:
1. Landed LHR T5 1849L unable to make EI177 @ T2. In response to the queries as to why I took this earlier non-BA CE option, contrary to an earlier post, I am not some grasping compo junkie demanding that BA rectify my errors, and view one of my responsibilities as a pax is to mitigate the airline's loss as much as possible, if I can. Getting out to DUB ASAP also gave me greater options and showed that I was willing to be flexible for the airline. Helpful for any compensation or insurance claim downstream.
2. BA T5 Flt Connections CS now booked all 4 of us on BA0826 for 2135-2259 hrs. TP and Avios earning legs back on for family.
The sharp-eyed among you will see that the scheduled arr time is 4:14 hrs late. Having already booked overnight HOTAC, an Avis rental and an FR Flt to Brizzle tomorrow, I won't be demanding anything of the airline as yet and will sort it in slow time once I get home.....unless those of you with this sort of experience suggest otherwise?
As I said earlier in the thread, every day is a school day; I've learnt a lot over the last 16 hrs (esp Corp Wage Slave's advice) and I am grateful for this forum's guidance, humour and experience, (a) for pointing me towards the ex-EU routes and (b) helping me sort my .... out.
And the wife just smiled at me....
Chin chin!