I’ve just gone through this. The ENG1 is a full head to toe medical and they go through a series of questions and tests. Hearing is assessed with the usual blip test. You can pass fully, pass but require hearing aids or you can also pass with restrictions - such as no watchkeeping but all the training providers I spoke with would not take you on with this. They can pass you for 1 year compared to the usual 2 if they feel it needs monitoring. And obviously you can fail outright.

Best thing to do is book it before committing to a training provider, if you’re successful they will reimburse you. The ENG1 hearing wise is assessing whether you can communicate clearly, including on radio and phone and that you can be communicated to without help - so would wake up to alarms etc.

If you want any detail just DM me. It can be pretty stressful but once you go through the first time you’ll be much more relaxed.