Strip-lynchets are medieval, as far as I know - I'm not an agricultural historian and dredge stuff out of unconscious memory - not always reliable. In Northumberland there was strip cultivation, and the ancient village strip, where I used to work, can be identified through later field boundaries. There were long strips that were cultivated by a single family, I believe, and my instinct is that these have partially survived as the allotment movement. The rent for the strips was harvest labour on the Lord of the Manor's crops. I guess the lord in Glastonbury would be the boss of the abbey. The notion of prehistoric sacred landscapes is ours, entirely. I've found a long cairn in rural Northumberland that appears to have had a sheep or cattle fold integrated into the structure, at the front. Assuming that the two features are contemporary - can only be proven by excavation, which is unlikely in my lifetime - then the sacred (burial of ancestors) and the profane (commercial farming) are intimately mixed and not, in any way, separate, as we prefer to see them.