Not the perfect solution, but one possible way to mitigate the problem and could be worth trying.
Where the phone line enters the house fit another two extension sockets immediately adjacent. Into one of those sockets install the telephone to modem adapter and fit the modem/hub very close by. This reduces the amount of cable that can pick up the RFI created by the TV. Run Ethernet to additional network sockets.
Initially make a small tin foil housing that the modem/hub can sit inside and if that works then get a nice looking metal enclosure
Use a DECT/cordless phone with mulitiple handsets rather than fixed/wired phones.
On the TV power lead, fit some Ferrite Beads - you may need to try/use different sizes. This will absorb the RFI being carried through the mains cables.
M H C
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