I'm really sorry to hear that you've been experiencing some pixelation on your BBC channels recently, and I'd love to help you out.
I've run some testing, and whilst everything is looking just fine at the moment, I can see around the time you were posting, we did discover an issue which may well have caused the problem you were seeing.
Are you still getting this issue? If you are please let me know so that I can investigate further for you.
I'm really sorry to hear that this is the case for you. I've run some testing again this morning, and can see some slight fluctuations in signal strength, so maybe it's best to get someone out to investigate things further for you.
I've sent you a private message in order to get this arranged. Please look to the top right of this page where you'll see a purple envelope icon, click on this and you'll see my message.