Had it not been for the extraordinary bravery, dedication and persistence of a relatively small number of young Allied combatants in World War 2, most of Britain's present generation would not exist.   That applies to many Americans, and others, too. Embattled England 1925-1945: Memories of the Great Generation is a unique first-hand account of Britain under attack by Nazi Germany, described quite differently from any previous ones by the author who grew up in war-torn England. It evokes a forgotten London that few knew, by an author who survived the Battle of Britain and the Second World War.  It also describes the horrors of bombing sorties over enemy lines without any protection from fighter planes, for which his older brothers volunteered to hasten the war's end.