Honestly, what's the point?
Just looked at what 4K TVs are available. Some of them are 85" diagonal - a bargain at £13K! Who the flip needs an 85" TV? Try getting a 40" and sitting closer to it.
What I can't see are any 20" 4K TVs for £250, which is what I'd want, if and when present, perfectly adequate, TV dies.
And would Corrie, X Factor or even those wonderful historical documentaries with Lucy Worsley be seriously any better in 4K?