Hmm, they were smashed in the 1640s and rebuilt in 1660, so there is probably no record of the original. So it's going to be a lot harder than a banknote.
https://upload.wikimedia.org/wikipedia/commons/a/a2/Winchest...The lead borders follow smooth arcs, so the glass may have been ground down to fit the existing shaped holes, causing a lot to be lost.
The caption seems to suggest all of the windows were broken, but only one side of the church was reconstructed with all of the pieces. So that's 3/4ths lost there, possibly.
I could see computer vision finding the orientation of symbols and faces, and gathering similar patterns. I'm not sure how much farther it would get though.