That's the best aerial view of Silbaby I've seen so far; and I agree, it does seem to show a mound lying next to Waden Hill. Whenever I've been there the vegetation has been too thick to have a good mooch around it.

Another thing which bothered me was: the mound doesn't seem to be higher than the road; you walk straight from the road onto the mound, and the road is in a cutting on its northern side.

baz