Hello - NATS medical consists of Eye Test, Hearing Test, ECG, Lung Output, Urine Test (For Drugs etc) reflexes, eye\ear exam, for us fellas the cup 'em and cough test, nice! Height and Weight also measured.
Think it takes less than an hour at CTC (I can't remember exactly)
Wear what you want as it'll take them less than 5 mins to get you out of your clothes and into a fetching robe! The ladies were very helpful and will put you at ease during the process.
Just a note on the Urine test, they'll ask what medication you have been taking for the last week, including paracetemols\Ibuprofen etc - So unless you have have a good memory, write it down during the week prior to your medica! Good luck