There have certainly not been any territorial restrictions in the past. This is the first time I have encountered the problem. I initially thought it may have been a slow internet connection which was impeding access - this can occasionally cause the site to be sluggish or time-out - but quickfile was the only affected site. Usually waiting a while allows the problem to rectify itself, but not today.
As far as I can see there are no other affected sites, and my present location (from which I have already logged in to Quickfile several times this month) does not block or censor the internet - unlike, say, China. Strange. It's not really a big deal, as I'm in now using the VPN. It just slows the system down a little.