I found a page that lists the material safety data sheets for Land Rover and Jaguar. If you look for LRN2279 (Land Rover XLR coolant), it says is a Prestone product "PRESTONE® OEM ANTIFREEZE/COOLANT". It has the same composition as "Prestone All Vehicles Antifreeze" according to its SDS: https://prestone.com/wp-content/uplo...SDS501_508.pdf

Prestone is $18/gal, Land Rover XLR is $45/gal.
Edit: https://sds.jlr.com/

 

I've been using the Wal-Mart 50/50 Prestone coolant for years. Zero issues, it certainly beats the DEX stuff that came with D2's from the factory.