Raining as usual when I visited this – and just couldn’t find a satisfactory place to park, ended up perched on the edge of the main road hazards flashing.. The field was FULL of enormous horses, who looked happy enough to see a visitor (until it transpired I had no food at which point they turned their bottoms to me to face out of the rain). But I felt rather small in comparison and didn’t dare go in with them. One was even stood on the barrow.
If you are more prepared than I was and can find a safe place to park, there is a legitimate footpath through the field and you will be able to see the chamber on the far side from the road.