It's a new feature. When you have your planner on the screen (all the programmes you've recorded), hit the left arrow button and the screen will move to a "tab" you can't see. This is a list of the programmes you've deleted. Can't remember how far it goes back, but I think it's quite a reasonable time.
Go to planner and press left arrow next to Select on your remote which brings you to ''deleted''.
You just scroll down and elect which programme you want undeleted and press the select button or the green to restore.