@pl_5309 thanks for the interesting article. I have Primary and Secondary DNS set manually. My router ( BiPAC 7404VNPX) does not appear to have DNSMASQ or PFSENSE settings.
Having said that, I actually think that my Check for Updates and EPG update issues are related to the hosted web app app.plex.tv/desktop referred to in this article Where is the new dashboard?, and not at all whether I am on a local host or the normal web host.
WHOOOHAAAA***STOPPRESS
I think it is a Google Chrome issue…Chrome is my PC default browser and the reason (potentially) that I cannot access the dashboard without the hosted web app and also the reason I cannot access Check for Updates and EPG updates in the normal web app. Wierd I know but I am experimenting further and will report back.
Batts