800,000-Year-Old Footprints Discovered in England Does it change anything?

This has nothing to do with history, you would have better luck asking in /r/anthropology.

The footprints are 800,000 years old, making them much older than our species. The authors are guessing they belong to Homo antecessor, a species that was morphologically intermediate between Homo erectus and Homo heidelbergensis. Probably the reason why they think it was Homo antecessor is because fossils of the same species are also found in northern Spain, at Gran Dolina and Sima del Elefante. These are about 950,000 years old, so it fits the timeline that they could have spread to Britain by 800,000 years ago.

The oldest actual human fossils found in Britain are much more recent - 500,000 year old human bones at Boxgrove quarry. That would correspond with Homo heidelbergensis.

800,000 years ago Britain was colder than it is today, more like the climate of Norway or Sweden. So it raises interesting questions about how cold adapted these people were, whether they wore clothes or furs, what kind of technology they had. But so far all we have is 800,000 year old footprints and some 700,000 year old flint tools, so not much is known.

The excavations from northern Spain seem to show that Homo antecessor was occasionally a cannibal.

As for relevance for our own species, we can't say at this time whether Homo antecessor was our direct ancestor. The generally accepted chronology is Homo erectus to Homo heidelbergensis to Homo sapiens. Or more correctly: Homo ergaster (African form of Homo erectus) to Homo rhodesiensis (African form of Homo heidelbergensis) to Homo sapiens.

Now you could put Homo antecessor in there and make it Homo erectus to Homo antecessor to Homo heidelbergensis to Homo sapiens. Or Homo antecessor could be a side branch, not ancestral to us. Or Homo antecessor might be an imaginary species, just another variant of Homo erectus that looks different enough to arouse naming-fever among some anthropologists. You have to remember, Homo erectus lived for a heck of a long time, over one and half million years. And over a huge range of climates and habitats, across the Eurasian landmass. So it's not unexpected that you would find specializations, local variations in this long time span. Whether they amount to a new species or not is more of a semantic thing.