I think I'm losing the will to live here...
I thought Stukeley was referring to 'Silbaby' and 'Silbaby' alone as Weedon Hill (see link to http://www.avebury-web.co.uk/silbaby.html ) in which case, and based on the fact that elsewhere in the country Weedon means 'Hill with a Welsh (British) Temple', it might indicate that 'Silbaby' was seen by the Anglo-Saxons as a (religious) 'structure' distinct from both Silbury Hill and Waden Hill.
That being the case it would reinforce Pete's discovery of a Silbury-type structure which he likes to call 'Silbaby' but which moss rightly says can't go through history with such a name (nor should it if Weedon proves to be the oldest know name ascribed to it and one which so accurately describes it as a Hill with a British Temple)!