The Bronze Age urn means it has possible/probable prehistoric provenance, so I don't feel bad talking about it now! ;) I must say I'm intrigued, and will certainly be doing some snooping on the subject...
I did indeed go the route you suggested (IE the other way!) but noticed the hill mentioned on the map to the right of where we were.
I can't help but think, as you've alluded to, that the "witch" legend could have older roots. I'm sure there's lots of demon/witch/monster stories around that were probably created to stop people visiting the site or worshipping at an old temple or sacred spot. Those bloomin' christians, eh? ;)
I've not seen the dew pond on Old Winchester Hill! Or rather I saw what I presumed was a dew pond but it wasn't surrounded by trees or owt. Maybe there's more than one? I'd love to hear more info about it though - where abouts on the hill is it? Our problem is that our young boy can't walk as far as we'd like, so by the time we get to the hill, he's had enough, so exploring is out of the question! I think an earlier start and a picnic might solve that one... :)
G x