You can restore any page (or post) you’ve moved to the Trash, by visiting Pages → All Pages (or Posts → All Posts) on your dashboard and clicking the Trash link above the list. It should show the pages (or posts) you have deleted and allow you to restore them.
Hey–that almost works! Except now I get an error message: “Error in Restoring from Trash”. I checked the box next to the post title, selected “Restore” from “Bulk Actions” and then ‘Apply”. Also tried the “Restore” link under the post title with the same result. Odd.