No interactions present.
I do agree it could be either and dissection was not done, however due to the location the likelyhood is that it is Grey. I will however make sure I record as psi/tridens when I send in my records to my local recorder.
Gardening for Wildlife
record these two confidently without dissection from the caterpillar.
Lat/Lng: 54.9, -5.2
OS grid ref: NX0061