You should prepare yourself for not having a very fruitful appointment. You need to self certify for 1week off work before they can issue you a med3/sick note. They can't issue them for the future so you'll need to contact them again after the first week if you still need more time.
Also whilst they don't tend to refuse medical notes I do wonder whether they'd say wrist sprain would be a valid reason to be off, obviously typing speed reduced single handed but i do think most employers will take a dim view in regards to multiple weeks off for what you've described. The GP can only really advise that you should return when you feel able to.
Secondly it's quite possible the GP won't be able to see the x-ray, often different systems are used and not accessible. They'd just see your discharge letter which can be quite minimal/might just say you've been discharged with wrist pain.
Essentially they're just going to check your neurovascular status, which will very likely be fine, squeeze your wrist to see where it hurts, which you already know, then try to reassure you you've had an x-ray and thats the standard test.
Even if they can see the x-ray it could have been years since they last interpreted an x-ray/might never have really done it depending on where they've worked. Anyone currently working in a&e is likely going to be more current. It's not normal to have all x-rays interpreted by an orthopedic doctor - anyone who's done the appropriate training course- that can include nurses, paramedics and of course any Dr. There's typically a secondary check or report by the radiographer so if something's missed they'd call you back.