I'm based in the UK and frustrated by this too - I recently bought my AirPods Pro 2 for this function. I spoke to a specialist in Apple's health unit today and pointed out that the regulations preventing Apple enabling this functionality were cancelled on 16th January 2025. Basically he didn't have any idea when the update would take place! I suppose the fact that Apple have enabled the Hearing Test is a step in the right direction but it certainly isn't the service I'd expect. I have four different Apple devices and it makes me think that loyalty isn't being rewarded...
It has nothing to do with Apple. It's the typical government red tape by the MHRA. It was announced in the Telegraph about 4 weeks ago that it is on its way. I posted the article at the time.
Any of your Apple devices NOT on 18.1? If so you can set the AirPods up as hearing aids with your older device.
Connect the via Bluetooth to the device.
Go to Settings/Accessibility/Audio & Visual/Headphone Accommodations
You will need the Mimi app to do your hearing test.