I finally succeeded in downloading the map update late last night - it took about 8 hours.
It installed it to BoA\Graphics\Regions with no problem.

I've deleted the previous downloads and I'm downloading it again now - about 1hr 15mins to go probably - I'll let you know what happens.

I've twice downloaded the map update and both times get 'Some installation files are corrupt. Please download a fresh copy and retry the installation' On the second download I got this at the end of the extraction (I didn't record this info on the first try) 'Extracting Winter_589Harrods Landing.bmp...