It's quite clear that we were all taught different things at different times. I never did Tudors and Stuarts at school, but did do Hammurabi and Babylon. We were never taught anything about US history (unbelievably) but did study Ireland from the Phoenix Park murders to the Civil War.
It's easy to point to English ignorance about Ireland by summoning Joe Bloggs, call-centre worker from Ashington, to the dock. But Joe doesn't know about Gladstone and Disraeli either or Chartism.
I don't think there's a special ignorance in the UK about the Empire or about Ireland. And, I remember, for a while in the 1980s it was impossible to have a discussion in England about the Troubles without someone mentioning Cromwell. Usually within 30 seconds of the discussion starting.
That's a good thing by the way.