Harlow Temple is admittedly a Roman site. But there’s good reason to believe that it was built on top of an Iron Age shrine.
“In the Iron Age Harlow lay on the tribal boundary between the Catuvellauni in Hertfordshire and the Trinovantes in Essex. At the temple hill there were two roundhouses of mid to late Iron Age date and numerous Iron Age coins, small finds and animal bones. The quantity and pattern of distribution of the coins, coupled with what appears to have been deliberate damage to the small finds suggests that the site had a religious rather than domestic function.”
see:
unlockingessex.essexcc.gov.uk/content_page.asp?content_page_id=120&content_parents=48,94
Beneath the Iron Age remains excavators found Bronze Age pits, some of which had fragments of burial urns. The EH book ‘Shrines and Sacrifice’ (Ann Woodward, 1992) also mentions Neolithic / early Bronze age flints which were also found, and suggests these lay on the original land surface under a purported destroyed barrow. Whatever, they do suggest a continuity of use of the site over a very long period (even if the flints do not relate to the later burials).