£310 is a crazy price; maybe you'd get that for an opalique, jet or pearl example, but standard colours like green usually fetch in the £30-£50 range on ebay. She's a later version too, which tend to fetch a little less than the earlier flowery examples. I also believe the black base isn't original. The fact that the same item (same photos and chipped in the same place) has been listed again after apparently having been sold, and that it's a private listing makes me very suspicious. The bid pattern of 40, 50, 60, 80, 100 looks odd too, and when was the last time you saw an auction where the bids were all round numbers with no odd pence?
While I can't say exactly what has happened in this case, I have noticed that since ebay started disguising bidder's identities, items often 'sell', then appear again several days/ weeks later from the same seller. It seems shill bidding is a more common occurrence than ebay would like to admit.
The earlier listing can be seen here:http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=380379516872
Re. the colour, I suspect pic. 3 is just a poor photo. The photos under natural light look the right shade for Jobling uranium glass, and I've thus far I've seen very little green Jobling art glass that diesn't glow.