Agree, British musicians pushed the envelope from the beginning in defining a sound whether that was the Byrds with "jangle" that is still a driving force with alternative rock or the Mercy sound of Gerry and the Pacemakers. And for the blues influence, the Stones were perfection and the inspiration for ZZ Top, the best white boy blues band.
What was so amazing to me was there was so little of the British Invasion until 63, it was all rock n roll and soul music, and the gates opened up and they came pouring through band after band and some with unique sounds I'd never heard before. It was just as if they'd been preparing for an invasion.
Being a teenager during that time, 63-68, was magical. The variety of top 40 radio with American rock, soul, Motown and the British Invasion all co-existing within the same format was astounding. There has been better music created since that time but as for a time in music, none better.