Dunaverty Castle (6)
I have added some lines here to show where the curtain wall ran, and a rectangle to show where the gatehouse stood.  It's notable that even with the man-made defences virtually completely gone, the natural defences are such that the only practical way to the top is through the location of the gatehouse.
dji077778 with lines scotland 2022 dunavertycastle southend kintyre argyll