Hey guys, found a fix by doing some experimentation with windows tools built into windows 8 to get the Windows 8.1 Preview update file to install.
Previously I was getting an "This update is not applicable" error and have posted a short and simple guide below on how overcome this problem. I am now successfully downloading the preview.
Download the update file from the Windows 8.1 preview site
1. Place and rename the MSU file in an easily accessible place, e.g. C:\8preview\preview.msu
2. open command prompt in administrator mode.
3. Type: Expand –F:* c:\8preview\preview.msu C:\8preview\
4. Type: DISM.exe /Online /Add-Package /PackagePath:c:\8preview\Windows8-RT-KB2849636-x64.cab
For some clarification, as this is my first post on the forum some people may be suspicious. Please see the Microsoft help article where I posted the same answer, and people replying that it worked for them!