Been up at Trig from about 1400hrs to 1530hrs. And can confirm Great Grey Shrike is there. After almost giving up on it, it re-appeared in the smaller trees in the corner of Lancelot, near the stile 50 yards up the boundary wall from the gate. Then coming down after leaving the Trig it was in its usual territory about 3/4 way up on the Dalton side (deforested area).
Also had a couple of Raven, and a few Meadow Pipits on passage. Very windy up there so you could'nt hear the Mipits that well.