Tvheadend

XMLTV plugins isn't working in your country? (guessing UK) ((SKY is operator in Germany and Italy also))
Is OpenTV: Sky UK activated?

WebGrab+Plus in not configured properly as I see in you screen-shots.

I'm not sure I understand.

What is wrong with the WebGrab+Plus configuration?

Everything looks OK to me in the Web UI, the EPG gets correctly populated with the listings for the channels I've manually added.

It's just the channels and listings aren't available on the clients.

Show client profile settings

This is the user used by the LibreELEC clients:

https://pasteboard.co/H0bRKHpr.png

is your client is in this network range?

Yeah. All the clients can see all the DVB-T2 channels and their listings. They just don't see the channels, or listings, for the channels created by the WebGrab+Plus EPG grabber.

WebGrab dont make/attach channels just EPG

So be more specific is channels are missing or EPG is missing?

p.s. is this are enabled

I've basically followed these instructions:

http://webgrabplus.com/documentation/interact-your-pvr-software/tvheadend

So the EPG Grabber I have enabled is:

https://pasteboard.co/H0cHunq.png

This resulted in the following EPG Grabber channels being available:

https://pasteboard.co/H0cK42b.png

but the channels and their listing were not available in the Tvheadend Web UI EPG so I manually created a channel (with tag "EPG Only") for each EPG source, eg.:

https://pasteboard.co/H0cIAEk.png

I can now see the channels and their listings in the Tvheadend Web UI EPG but neither the channels or their EPG listing are available in any of the remote clients (LibreELEC or TVHClient).

Install xmltv and test with other grabbers

Tested with other XMLTV grabbers and the results were exactly the same.

After further testing it turns out that the problem was that the "dummy" channels I had manually created were not associated with a service. I added any available service to the channels and now all the clients show the channels and their EPG listings.

I'm not sure if it is possible to create a "dummy" service to associate with the "dummy" channels, rather than using a real service, but at least I see the correct EPG listings on all the clients now.

You can just create an IPTV network, add a ts file as a mux (using file:///path/to/my.ts) and map it as a service.

Great minds think alike, already done :-) Many thanks.