I managed to fix the update issue on my laptop by renaming bdcore.dll file to bdcore_old.dll, I then performed an update and this time it was succeeded, the update also pulled down a new bdcore.dll file.

File location:
C:\Program Files (x86)\Spybot - Search & Destroy 2\av

It does look like the original bdcore.dll was corrupt and was preventing the antivirus updates from working.

Thanks,
Martyn