It downloaded 64-bit, I was running 64-bit when running the upgrade assistant.
However it downloads just the install files "C:\ESD" (hidden folder) and comparing the original 64-bit disc from TechNet, there is alot of differencies. 64-bit for Technet is 3.33 GB and this is 2.61 GB, this doesn't have install.wim, it has install.esd which is 1.96 GB, install.wim from Technet is 2.68 GB. I guess install.esd has some skus removed.
Just tested and the key works fine when doing a clean install from Technet disc
Is there any way to get the 64 bit install media whilst on 32 bit?