My only problem with a formal zebra crossing is that you would then have to have those grotesque flashing yellow beacons too (i believe so anyway) and I think Avebury has far to much street furnitures as it is (and it would ruin my photography). Maybe reducing the speed limit to 15 or maybe 10mph between the banks and giving pedestrians priority like they do in some town centres is the way forward. This would help wheel chair access too I would imagine. I also like what they did at the Rollrights for wheeled access so something similar would good.
I wouldn't like to stop vehicles (cars and buses anyway) from going through the village as this would be unfair on the locals trying to go about there business.
To be honest, I have loads of ideas which will never come to fruition. Mostly though, I hope it doesn't get any worse than it already is now.