Before I had to send back the Vodafone Nokia Lumia 635 (which was kindly loaned to me). I had to put Windows Phone 8.1 back onto the handset (as I had to remove the Windows 10 Technical preview).
Note: The price of the Nokia Lumia 635 from Vodafone is now £75 or free on a £14 a month contract.
This video documents the process I used.
Here is the link to the Recovery Software:
In Part 1 I look at the Start Menu, All Apps Menu, Notifications, Phone Dialler, Text Messages and the Windows Store.
In Part 2 I look at the Camera app, The Lock-screen and Cortana.