cost of screen replacement on an iphone xr

iPhone Repair - Screen Damage [and links to other iPhone repair services] - https://support.apple.com/iphone/repair/service/screen-replacement - includes pricing (note, third party AASP may set their own prices).

Seems to be $29.

An iPhone XR, out of warranty should cost £196.44 for a simple screen repair and replacement however in your case, with Apple care, a screen repair of any iPhone should only cost £25

this information can be seen for yourself in the following link:

https://support.apple.com/en-gb/iphone/repair/service/screen-replacement#applecare

Yes, pretty much what I indicated much earlier. ;-)