Getting upgrade to to build 1511, 10586 offered through update now.
I'll let you know how I get on guys.
Upgraded Ok to Windows 10 Pro 1511/10586.3 using windows update.
Only one small problem to date. After the update and the first appearence of lock screen, the mouse was dead (Microsoft Intellimouse), cursor visible but no movement or click response.
Pressed escape key to get to the login screen and logged in.
After logging in there was no mouse cursor.
Rebooted using the keyboard and mouse is ok now.
Everthing seems ok initialy, but I'll investigate further.
Edit:
As I read elsewhere previously, after the upgrade some defaults are altered. Irfanview still handles gifs by default as previously set, but pdf handled by Edge by default now, rather than my previously set
acrobat reader. Probably other changes too, so you may want to check your program defaults after your upgrade.