g1smd - 3:54 pm on Aug 31, 2013 (gmt 0)
If you have a redirect in place you do not need to remove anything.
The redirect already says "it ain't here - look over there".
WMT data doesn't exactly reflect the real world. I'd let Google figure it out.
Are you sure they can still crawl the old URLs and are doing so? Do not block with robots.txt.