retune

I had to retune my TV (Panasonic VT series) a week ago. And I've lost about half of my HD channels. I've lost Channel 4+1 HD, Four7 HD, and most importantly, BBC News 24 HD. I've got BBC 1-4, ITV / STV, and Channel 4, and that's it. I've tried retuning several times over the past few days. How...