On May 29, 1919, British astronomer Arthur Eddington recorded the first experimental proof of Albert Einstein's theory of relativity by observing stars in their "normal" appearance and then again behind a total solar eclipse. When Eddington and colleagues confirmed that Einstein was right later in the year, The Times (of London) published a front-page article with the headline "Revolution in science! NEW THEORY OF THE UNIVERSE: NEWTONIAN IDEAS OVERTHROWN" and Einstein became an international celebrity.
How much would that article have meant to the average English reader of The Times? Would they have understood Newtonian dynamics and what Einstein was suggesting enough to recognize that this was a big deal? What was the general level of science literacy at the time?
Also, given that the Times story was published four days before the end of World War 1, was this mainly big news because it was a distraction from war?
I would guess it would be similar to the LIGO detection of gravitational waves. The general public might hear about it and those who care enough to find a cursory explanation of what happened would do so. I assume the majority of British people reading the Times in 1919 would not have the education to understand the true significance.
These are all assumptions but given that the average person even now doesn't really understand Newtonian dynamics beyond a shred of what they might remember from school nor do they understand relativity beyond some vague concepts they have in their head from sci fi films or wherever else. I find it hard to believe the average person in 1919 would understand the true significance.