The details in your post are v interesting for me as I'm very new to this and didn't know of these trends in the RA.

I went to the plantation site after visiting the Ringses. I couldn't believe the Ringses were defensive in any way as you could literally lob stones in from the surrounding ground. So after an afternoon there I went on the maps looking for nearby high ground that could be defended.

This led to the plantation site, and while I still have doubts about defending that site it's a lot more practical than the Ringses from that point of view - also a lot more impressive to anyone passing, being on the ridge line.

I tend to look for new sites following rivers and/or ridges (I did a lot of walking when younger and that always seems to be how people travel on foot). Link that to big collections of people usually happening where travel links cross and that's my logic.

I would bet that here's more "stuff" near the plantation site, there's the cist marked on the map just south in the woods but if you look at the area there's a u shaped block of raised land surrounding Titlington burn that links Huntershugh round Titlington Pike to Jenny's Lantern that has numerous "settlement" and "cairn" locations marked on the OS map.

Beanley Plantation is on the north edge of this before the land drops away towards the River Breamish. So if you join the dots between the sites already there on the u-shape section of land I would expect there will be other new sites/maybe RA.....

Fun, this is :-)