The Hankook Ventus S1 evo3 SUV K127C HRS and the Pirelli P Zero (PZ4) Run Flat are available for BMW X5 tyres at Tyres.co.uk. They are available for the front axle of G05 X5 models with 20-inch staggered wheels in the dimensions 275/45 R20 110Y XL. Please match the rear-axle fitment and keep the XL and run-flat specifications.
Details about the BMW X5 tyre sizes can be found on the tyre-pressure information sticker located on the driver's side door pillar. The sticker shows the approved specifications for tyre sizes and air pressures for the front and rear tyres. Since the fitments on X5 wheels are staggered, be sure to reference the sidewall of the tyre and the owner's manual.
It is not always necessary to replace all four tyres on the BMW X5 models, however, the xDrive all-wheel-drive versions require all four tyres to be matched in brand, tread design, and tread wear. When possible, replace tyres as pairs per axle. If you put new tyres on one axle, UK tyre safety recommends that you do so on the rear axle.