I do not know the details of what is required in UK, but typically a LED lighting device got a typical lifetime of about 10-20,000 hours if left continuously on. This is well beyond the useful lifetime of CT's traction battery.
Here in the US, Toyota Motor has to certify that all new cars meet the minimum safety requirements of the NHTSA, i.e. if there is a requirement to have spare headlight bulbs they must provide in every new car they sell. For example, BMW no longer provides spare tires so they decided to equip as part of OEM RFT's in every new car they sell; which in turn safes weight and improves on CAFE. BTW RT's makes the BMW ride like a concrete truck.