Baker's Hole at Ebbsfleet in Kent is an old chalk quarry situated next to a big railway station on HS1 and contains sediments going 250,000 years ago – which include Palaeolithic remains (Neanderthal). Stone tools, mammoth teeth and fossilised bones of deer, bison and lions have already come to light. See http://phys.org/print335608632.html
The chalk in Kent represents the youngest strata in the country. Most of the Upper Chalk has been eroded away north of the London Basin – in some places washed out all the way down to the Middle Chalk formation (near the escarpment). Hence, research into the Younger Dryas boundary event will probably have to focus on Kent and Sussex rather than the Han Kloosterman lost site at Pitstone near Tring.