Hi Chap
I'm afraid the embedded google map isn't working. If you mean the feature located in the second field from the farm to the south east, which is bounded on the east by the stream, then that looks very much like an infilled quarry, the vague figure of eight is characteristic because of the method of stepping the sides to enable access and egress. Or it is possibly a geological feature as these can also have this sort of shape.
Interestingly if you look directly north-east of Sionhill farm at:
51.56.11.96 0.54.09.52
You can see an archaeological evaluation in the form a of a series of long thin trenches. Wonder if they turned up anything?
Something is not right. This message is just to keep things from messing up down the road