Not trying to stir anything up, but IMO - I think Jimmy Page is lying.
In the early years, LZ opened for Spirit, and I am sure they heard many of their songs including Taurus. I wouldn't be surprised if all the LZ members had the 1st four Spirit albums in their personal record collections in those years, because they are fine albums.
I don't know what is at stake here financially, but it is clear to me that their is some resemblance of the beginning of STH and a passage in Taurus, and I wouldn't be a bit surprised if LZ was influenced by it and actually "stole it", like so many of their other songs...