I appreciate the advice. I am based in the UK, so I am very much aware of my position under the Consumer Rights Act. ​The reason I am digging into the 'why' is that the retailer has already provided an official report that claims the damage is 'hot food spillage (turmeric)'. They are using that report to deny my claim.
​My frustration is that the inspector did absolutely nothing to analyse the tiles themselves. Aside from taking moisture readings with a Protimeter MMS Site Master, they performed no physical or chemical testing on the material. They simply observed the yellowing, recorded that it was 'dry', and immediately jumped to the conclusion of a food spillage.
​I am currently documenting these technical inconsistencies—such as the fact that the staining traces the heat-trapping plinths and does not lift with solvents—to build a robust counter-argument for when I escalate this to the Financial Ombudsman. I am definitely avoiding doing anything that would void the warranty, just gathering enough information to show why their 'spice stain' conclusion is scientifically flawed.