Technically the British Iron and Bronze Ages are prehistoric since British recorded history begins with the Roman conquest in 43 AC.
I also think it's funny that Schama's History of Britain Volume 1 is titled "3000 BC - AD 1603" and yet only has 6 pages of information for before 55 BC, and certainly nothing specific date-wise that would justify choosing 3000 BC over any other random year.
I think I initially was going to write paleo/mesolithic but couldn't remember how to spell mesolithic.