Apologies if this is mentioned elsewhere in the thread, but I need to go kip and haven't time to read.

It's sort of related, but if you have a look at a few of the small hillforts up here in Northumberland, it's evident that they seem to be built in militarily poor defensive positions, usually by way of being closely overlooked by adjacent slopes, yet they also seem to have been constructed to surround significant natural features or rock art. Like a deliberate control of access to the evidence of the ancestors.

If you go for this line of thought, then the most interesting example is the cup marked stone in Corbridge roman fort, where the stone may have had it's own dedicated building within the fort, which itself was built by legionnaires from Galicia in northen Spain, another area that has a lot of cup and ring marked rocks. You could then extrapolate to infer that in some areas of Europe, in the iron age, there was, at the very least, still *some* special significance imbued upon older monuments. Which seems reasonable enough a statement to me :)