I am a student and I got a key through DreamSpark/MSDNAA for "Microsoft Windows 8 Professional 32/64-bit (English-Great Britain)". I tried to download the iso with Secure Download Manager, but after 4 hours of struggling a I couldn't get even 7% of the file. So I am downloading it from a different source, but It isn't an en_gb version, "Microsoft Windows 8 Professional x64 MSDN ENG" (en_windows_8_x64_dvd_915440.iso). My question is, Can I activate the English version of Windows 8 with a en_gb key? (I think English means en_us)
I don't think the language will be an issue, but the fact your now downloading a different edition (MSDN) would be.
I would instead try another pc to do the download. Or if you know someone who has successfully burnt the dreamspark ISO to DVD you can just legally use that.