Selling MBPR, erased drive and cannot install OSX

Question

Ok, so I am selling my early 2013 MBPR so have backed it up, erased the hard drive, but now cannot even reinstall OSX on it.
The MBPR came with Mountain Lion, but I have upgraded to Mavericks. I think this is what was causing the issue maybe?
I get an error message on a grey screen saying: Apple.com/support -3001F (see image)
How can I reinstall this software? I am now having to load from an old backup which is a pain in the ***, just so I can reinstall OSX.
I followed these instructions:
  Re: Wipe/Factory reset of my MacBook Pro Retina that I just sold?
    Sep 20, 2013 4:49 PM    (in response to rmreid09) 
Follow these instructions step by step to prepare a Mac for sale:
Step One - Back up your data:
       A. If you have any Virtual PCs shut them down. They cannot be in their "fast saved" state. They must be shut down from inside Windows.
       B. Clone to an external drive using using Carbon Copy Cloner.
          1. Open Carbon Copy Cloner.
          2. Select the Source volume from the Select a source drop down menu on the left side.
          3. Select the Destination volume from the Select a destination drop down menu on the right
              side.
          4. Click on the Clone button. If you are prompted about creating a clone of the Recovery HD be
              sure to opt for that.
               Destination means a freshly erased external backup drive. Source means the internal
               startup drive.
Step Two - Prepare the machine for the new buyer:
          1. De-authorize the computer in iTunes! De-authorize both iTunes and Audible accounts.
          2, Remove any Open Firmware passwords or Firmware passwords.
          3. Turn the brightness full up and volume nearly so.
          4. Turn off File Vault, if enabled.
          5. Use Boot Camp Assistant to remove a Windows partition, if there be one.
          6. Disable iCloud, if enabled: See.What to do with iCloud before selling your computer
Step Three - Install a fresh OS:
     B. Lion and Mountain Lion (if pre-installed on the computer at purchase*)
         Note: You will need an active Internet connection. I suggest using Ethernet if possible because
                   it is three times faster than wireless.
          1. Restart the computer while holding down the COMMAND and R keys until the Mac OS X
              Utilities window appears.
          2. Select Disk Utility from the Mac OS X Utilities window and click on the Continue button.
          3. After DU loads select your startup volume (usually Macintosh HD) from the left side list. Click
              on the Erase tab in the DU main window.
          4. Set the format type to Mac OS Extended (Journaled.) Optionally, click on the Security button
              and set the Zero Data option to one-pass.
          5. Click on the Erase button and wait until the process has completed.
          6. Quit DU and return to the Mac OS X Utilities window.
          7. Select Reinstall Lion/Mountain Lion and click on the Install button.
          8. Upon completion shutdown the computer.
     C. See What to do before selling or giving away your Mac
*If your computer came with Lion or Mountain Lion pre-installed then you are entitled to transfer your license once. You must remove the computer from your list of registered hardware. If you purchased Lion or Mountain Lion from the App Store then you cannot transfer your license to another party. In this case you should install the original version of OS X that came with your computer. You need to repartition the hard drive as well as reformat it; this will assure that the Recovery HD partition is removed. See Step Three above. You may verify these requirements by reviewing your OS X Software License. See Terms and Conditions if you need to transfer an Extended Warranty that is still in effect (Transfer of Plan.)

Answer 1

Thanks LowLuster.
So after restarting while pushing Command + Option/alt + r, I get the globe on the screen for Internet Recovery.
Next step is to erase the hard drive (Macintosh HD)
Then reinstall OSX?
I'll give this a go, but I can't see the option for 'Disk Utility to Repartition the drive as One Partition to Remove the Mavericks Built In Recovery HD partition from the internal drive' - all there is is the usual disc utility to erase it?
EDIT: It's now letting me reinstall Mountain Lion after erasing the hard drive, excellent