The main motif is clear enough, but the others are rather faint. It's north facing position isn't exactly the best to show up the fainter carvings, as it looks as if it's usually in the shadow of the building.
It's worth a visit, as the centre has a nice little exhibition of local finds, not many, but recompense for this exists in the form of the various informative video screens detailing the heritage of the valley, with a strong emphasis on archaeology. It's a good spot to start from if you want to explore the high density of reasonably well preserved prehistoric settlement nearby. Also a good spot to pick up a replica bronze age pot, should you like such things.