install .net 3.5 on fresh azure windows 10 vm gives error code 0x800F081F

In azure create a new Windows 10 Enterprise N compute instance. Log onto the box and use Turn Windows features on or off to add .net framework 3.5 it errors with error code 0x800F081F

I've googled everywhere for this and there seem to be loads of advice to uninstall various updates but I haven't got any, all I'm left with is this from microsoft https://support.microsoft.com/en-us/help/2734782/.net-framework-3.5-installation-error-0x800f0906,-0x800f081f,-0x800f0907

To fix the error codes for Windows 10, follow these steps: Download the Windows Media Creation tool, and create an ISO image locally, or create an image for the version of Windows that you have installed. Configure the Group Policy as in Method 2, but also follow these steps: Mount the ISO image that's created in step 1. Point the "Alternate source file path" to the ISO sources\sxs folder from the ISO. Run the gpupdate /force command. Add the .Net framework feature.

Really? Is this going to be the case with all windows 10 boxes or is it just because I'm using an azure VM?