Pixellation is indicative of a problem with your TV signal, it's a fault that VM should be able to rectify once you report it. Netflix and other streaming apps are carried over the internet and don't use your TV signal.
The V6 is indeed a newer box, but you need to have VM broadband to have one. If you have broadband, there would be no harm in asking VM for a swap if your box is deemed faulty.
Your alternative is to look at your overall TV package, and if you've had it for a while, then investigate whether a newer bundle may be more cost-effective and could also include a box-swap.
I'm a Very Insightful Person, I'm here to share knowledge, I don't work for Virgin Media. Learn more
Have I helped? Click Mark as Helpful Answer or use Kudos to say thanks