As I've had a few goes at trying to connect with the Poppy Hill Great Grey Shrike I thought I'd make a map for anyone else interested in going for it. It also seems to be staying in more or less the same set of bushes in recent days too, which makes things a little easier. The map below details where to view from - the metal gateway overlooking the railway; see here:
Just to the left of the Network Rail sign, at the back of the field, are the bushes the Shrike has been hiding in. For the last couple of days it has often been either at the very base of these bushes or buried within them - sometimes coming to sit on the outside. Like this:
The bird does move around quite a bit but has tended to come back to these bushes regularly recently. There is a track just the other side of the favoured bushes which cars and tractors use. If one goes past keep an eye out as this often makes the Shrike move - often flying a little way before going back in again. Best of luck!