I've managed to 301 everything except that pesky %20 url, perhaps because of the %20 or perhaps because that's also the only one in a folder.
Here's what's worked for simple urls such as www.site.com/old-page
RewriteRule ^old-page$ http://www.site.com/new-page [R=301,L]
But the same format for the %20 hasn't worked:
RewriteRule ^/products/product-name%20$ http://www.site.com/products/new-url [R=301,L]