and from the first set of exclusions in that link TJ
While you can claim for most property damage or personal injury, there are certain types of damage explicitly excluded in the Consumer Protection Act.
Loss or damage to the product itself
Damage to business products not ordinarily intended for private use
Damage to property with a value below £275
In cases like this if the shop doesn’t want to deal, ask them what the importer told them? If you get no joy from the shop call the importer. You may be able to get a new headset but riding it after it went – was there really no noticable play in the steerer (there would probably need to be to damage it) will not help as you have caused the damage yourself at that point.