If the insurer has said they will be led by the surgeon you either need to contact the surgeon to get confirmation they are happy for you to drive or, if you were given a pre-op information pack by the hospital it may be written in there. For example, a lot of the big hospitals state in their RP information leaflet to patients that they should not drive for 4 weeks - if you ignored that and had an accident you wouldn't be covered even though you hadn't been explicitly told.
Some surgeons will just confirm verbally you can drive at the 6 week post-op review
Some insurers don't say anything about the hospital or surgeon, just that you must be recovered enough to be able to do an emergency stop safely.
My husband was at the other end of the scale. He had a company car at the time and the insurer wouldn't cover him until they gad a letter from the surgeon which the surgeon refused to provide ... in the end it took 12 weeks before he could get behind the wheel!
Google will quickly tell you whether your hospital has a stated position on driving after abdominal surgery