Wife has a Corsa with 185/55 x 15 Michelin's.
These are fairly perished and were an advisory on the MOT.

The tyres are 4 years old and have loads of tread left on them, as she only does about 2,200 miles per year (car's only done 8,200 miles from new).

I wanna stick some new boots on it, but don't want to splash out on Michelins if they are going to do the same in 4 years time.

I can get Pirrelli P6000 for £40, but I had P6's year's ago on a car and they also perished.

Was think of Toyo's or Falkens as can get both for £39-£40.

Any help appreciated......

 

Think most tyres will perish in that length of time whether driven for miles or not.

Consider they are exposed to the elements, especially UV light, and having the weight of the vehicle pushing on them.

Try using some form of tyre protector/shiny dressing stuff. This may help the side walls cracking and deteriorating.