"Were the earthworks put there because of the RA or was there a primary reason that was the cause of both ?"
My money is on the latter.

I reckon that people recognised, for whatever reason, the Chatton landscape as significant to their lives, a place of power for want of a better word, not power as in power over others but power of place...Djang .
That whole hillside the beautiful Chatton carvings, the views over the landscape, the enclosure with it's unique and enigmatic carving and then, the icing on the cake the lovely megalithic lino-lined Ketley rockshelter.
There we go again - rockshelter, the terminology undermines the significance of the place.
Rockshelter implies a sort of sub-cave, somewhere for a shepherd to chill etc.....Ketley is so far beyond being a mere rock shelter that I have trouble finding words to adequately describe......I'm going off on one aren't I ? but hopefully you'll know what I'm getting at - maybes aye maybes nay!