Two Thousand years ago is Roman times. The Roman sources, as far as I know, do not reference human sacrifice in SW England, where the Durotriges Tribe was located.
The SW Britannic tribes of the time did have a written language, although, as far as I know, they did not use it much. It may have been Gaulish, Greek or even Latin.
Roman conquest of Britain started in AD 43 (Emperor Claudius), with Wales finished up in AD 77.
The Scots were in Ireland until a century or so after the Roman Empire left Britain; the tribes of Caledonia weren’t too much for the Romans to handle, there just wasn’t anything of value there, and demands for military force on the continent was more common.
These conditions led to the construction of an earlier barrier apparently following the approximate route of Hadrian’s Wall but in turf and timber. The Antonine Wall was a later turf-and-timber barrier farther north.