That's not quite right. It is true in the absence of any other stated guidance or position but:
- if the hospital provides a leaflet to patients (or has something on their website) stating a specific timescale, that applies even if you haven't read it or had your attention drawn to it. So if the hospital leaflet says two weeks but you decide after 10 days that you can do an emergency stop, your insurance is invalidated
- if the surgeon tells you that you can drive after 2 weeks, your insurance would be invalidated if you drove earlier, even if you feel on top of the world
- if your insurer has a policy of 4 weeks after abdominal surgery (as many do), you would invalidate your insurance by driving earlier, even if you felt fine and the surgeon said it would be okay after 2 weeks
- if your insurer requires written confirmation from the surgeon or GP that you are fit to drive, you have to do so
The 4th situation was the one that John found himself in. With a company car, his employer's insurer required a letter from the surgeon to confirm J could drive but the surgeon refused to provide this as he said he had no way of knowing for sure. In the event, it took 12 weeks to sort out :-(