Thanks, I had already been able to replicate the fares on Expedia - .co.uk and .com and am hoping to use that site - but - I am still amazed at that regional price difference, it is shocking. I have no idea what it is based on or how it is calculated but I would have thought it would be around 15-20% at most.

Thinking more on it, not sure this is regional pricing or something else (unknown) entirely. There is another flight on those same dates
DUB 0950-1725 MCO
MCO 1255-0730 DUB
which on the united.com Europe-UK site is coming in at roughly the equivalent of $3100. It looks more like certain flights are being pushed to Americans and different flights to Europeans.