Hello all / I bought my bike with Pirelli Diablo Strada fitted - front looks fine (and feels fine) but is 10 years old, rear is very squared off and feels odd but otherwise ok tread wise. With no way to 'unsquare it' (I thought maybe a bike tyre lathe might exist

) I guess I have to open my tight wallet. So, in the UK these seem to be the cheapest branded tyre deals (for a pair as I assume 10 years is too old??) and I wondered if anyone has any experience of them?:
Metzeler Z6 £138, Pirelli Diablo Strada (again) £140, Continental Contimotion £144, Dunlop GPR-300 £138. Any thoughts?
The Dunlop and Conti describe their product as the 'value' choice, whereas the Metzeler is just a 'sport touring' tyre. The Pirellis are old stock I think.
My thinking is the Metzelers were OEM fitment and don;t use the word 'value' so maybe best? The thing is I NEVER ride in the rain, so tread etc isn't an issue. But I do ride slow and often two-up so resisting squaring off would be useful. Sadly that test parameter is never, errrm, tested.
Any thoughts?