What you might also take into account is that the US Civil War finished a mere 155 years ago. Given the conditions and philosophies under which it was fought and the lingering effects that it has on the US today, its not surprising that it hasn't been "forgotten", and it may well live on in family memory. On the other hand, the English Civil War(s) ended nearly 370 years ago so its not surprising that its influence on folk memory is nearly zero.
An interesting factoid is that Oliver Cromwell was on the verge of emigrating to the Colonies at the time and that if he had gone, the absence of his charismatic leadership may well have resulted in a victory for the Royalists.
Quick someone, find a joke to get the thread back on topic!!!!