[Maki]

Is it worth upgrading TV coax from the wall socket to the TV, ie Russ Andrews?

[Brogan]

Why?
Do you believe your current cable is degrading the signal?

Also, what's the point in 'upgrading' the cable from wall socket to TV if you first don't 'upgrade' the cable from antenna to wall socket.

You can't get any better coax than the double shielded stuff they use for satellite installations so if you really want to change your cable, make yourself a flylead using a length of that and a couple of connectors.
Shouldn't cost you more than a few quid.