ok ive finally manage to download the patch after 3 days of trying. not really sue if it was anything i did or if i was just lucky and the problem has sorted itself. anyhow heres what i did.

first go into youre documents , my games, then ffxiv folder then downloads and delete the partially downloaded patch file (the one that keeps failing) and i even deleted the ffxiv updater as well (bascally everything in the download folder)

Then i turned of everything, and i mean literally everything. My firewall, my antivirus and in task manager i closed all non essssential windows processes.

then launch installer and fingers crossed. hope this works for you guys. ^__^