Can't install .net framework 3.5 on Windows 8 (Surface Pro) error 0x800f0906, no installation media available

I get the same error as in this question: Error 0x800F0906 while installing .Net 3.5 on Windows 8

However the Surface Pro didn't come with installation media so I can't follow the offline installation as advised in the answer to that question.

Also not sure why this doesn't work, I can access the internet fine, can install updates OK, and can access www.update.microsoft.com.

Download the 64Bit Windows 8 Enterprise Trial, mount this ISO and run the DISM command

Dism /online /enable-feature /featurename:NetFx3 /All /Source:x:\sources\sxs /LimitAccess

You can also uninstall the security updates KB2966826 and KB2966828 and then install framework from the control panel/ program and features/ turn windows features on