It's a very minor pair of bits of rock art, but worthy of mention for a couple of points.
One is the dumbbell motif, unusual, especially on a portable. Similar to the one on outcrop at Fowberry cairn.
Also, the old boundary earthwork (linear, definitely a post roman feature) appears to run right through the remains of a bronze Age cairn. There's a lot more stone in the earthwork the closer to the RA you get, sort of implying that the cairn was stripped to provide building material.
Thus, it's reasonable to assume that the marked rocks came from the cairn, as is quite common. So maybe there were/are more still in hiding?