Two tyres on the same side worn

[uk_friendly_fire]

Michelin tyre 20,600 miles so far. 1.2 and 0.9mm above legal min. Looking to buy Hankook replacements.

How should they be replaced?
Is it acceptable to move the right rear tyre to front left and put two new ones at the rear?
Any wisdom on this

[Gryffindor]

I was going to do the same with my C4GP at next service. Obviously, 4 new tyres are far better, but my wallet isn't that big.
I suggest put the new tyres on the engine-driven wheels.