Mylarx - it certainly appears to have returned! That covering thread refers to HUGE problems encountered by dozens of users for well over a month, as in http://en.forums.wordpress.com/topic/unable-to-load-the-webpage-because-the-server-sent-no-data/page/11?replies=312
Users contacting ISPs is unlikely to solve problem of WP servers failing to load because of ISP connections issues. Respectfully suggest it's for WP managers to crack heads, as implied in above supervisory thread.
Have lost changes to a draft without any warnings whatsoever even after saving apparently worked normally. Just before that WP failed to load a new image. Yesterday afternoon I noticed everything was taking a while to connect and load, which made me suspicious. It reminded me of events last July!
Unfortunately cannot use back-up from browser as it's just auto-updated from IE10 to IE11 and it seems this updates itself frequently so there's no difference between it and WP autosave. Tried using Chrome but that was worse!
So will work in Live Writer and try copying/uploading rather than edit direct in WP direct.