I seriously doubt there were 70,000 Romans for Boudica to kill at the time, but that's beside the point.
https://www.cambridge.org/core/jour...e-remodelled/A118920A90FB7CCB2838CEEB10BE477D
This paper highlights no significant activity after the Middle Bronze Age when it appears people began chipping the bluestones to make artefacts, which essentially constitutes looting, not continual occupation. After that there's basically nothing until the later medieval period.
Timothy Darvill, VPSA, and Geoffrey Wainwright, PSA gave a report on the 2008 excavations which is available here to anyone with Athens Access:
https://www.cambridge.org/core/jour...vations-2008/AB2CE78C311F161EC7B876A443C50AEA
The shaft you seem so exercised about appears to be Roman, not Celtic.
"Fully excavated, the shaft is substantial and, of course, it chops out a lot of earlier stratigraphy. In the bottom was a very strange piece, which some have likened to the phallic stones found on Neolithic sites. Certainly it is a long, thin, spiky piece of natural flint nodule. There was abundant Roman pottery from the fill and another late Roman coin on the base. Also from the shaft came a substantial amount of animal bone – more than 400 pieces all together – which Mark Maltby has been working on. There are bones of sheep, goat, pig, horse, dog, red deer, hare and rabbit, and two species of bird, fowl and wader. So we now have structural evidence for the use of Stonehenge in Roman times – mainly in the late fourth century or a little later – with the shaft for sure, and perhaps a pit or a grave against one of the sarsen stones as well. We have bluestone incorporated in both those structures, suggesting that, during this time, pieces of the bluestones around Stonehenge and within it were being broken off and used in the construction of these features. We might note that earlier excavations recovered some twenty other Roman coins, half of which are also of fourth-century date. There are 1,857 sherds of Roman pottery from previous excavations, and at least seven items of Roman metalwork. All together, then, there is a substantial collection of material; in the past this has been interpreted as being from Roman picnickers; now perhaps we need to rethink what this material really means for the use of the site as a place of ritual or ceremony in the first millennium AD." (p. 15)
So we have some possible ritual activity in the late 4th Century, which is Centuries after
Druidic religion was supressed. As always we must bear in mind that Roman Polytheism was highly syncretic - the Romans would interpret local Gods as local manifestations of their own deities and were not shy about adopting local practices into their rituals. That doesn't mean Druidic continuity, though, it means a Celtic layer applied to what is still largely Roman practice.
The majority of what they record is further vandalism, i.e. bluestones being chipped and carried
away to be used elsewhere.
"Bluestones at Stonehenge were clearly broken up in later prehistoric times, and in Roman and medieval times this became quite an industry. The bluestones were differentially selected for removal. As Paul Ashbee once noted, almost all the sarsen stones are still there, but something in excess of two-thirds of the bluestones have disappeared. Close examination of the bluestones at Stonehenge reveals the presence of large flake-beds on the stones where rock has been detached (fig 10). In the case of Stone 35a almost all the rock that originally protruded above ground was removed. Such removals contribute not to the shaping of the stones but to the removal of pieces for use elsewhere. Clearly, stone removal was happening in post-prehistoric times and continued down into more recent times."
So this means the locals continued to value the stones, to some degree. The question of who those people was in an open one, though? Cunning Folk, perhaps? Crucuially, what there is NO evidence of (excepting this one late-Roman shaft and another burial) is sustained ritual activity
at the Stones. This is the key point - whilst the Stones may have continued to hold a fascination they were not in regular usage as a communal ritual site and the literary evidence underscores a general disinterest in them.
Near where I grew up there's a Stone called the "Devil's Stone" which is said to be the lock on his prison in Hell. The stone is still turned every year on the 5th of November to keep his prison secure. It is said if this is not done the Devil will escape and bring disaster to the village. This is probably some remnant of a pagan memory - but the turning is done by the local
Christian bell ringers.