Mole,
You have worldwide medical cover so your outport doctor's visit is 100% covered. I have submitted many claims and they have always been paid, albeit at the usual snails pace of CX admin. If you cant get into a walk-in clinic then I suggest you go to the ER, even for a common cold, they will fit you in when they can. ER visits to foreigners are typically at least 5 times the cost of a walk-in clinic, another own-goal for CX and their misguided policies.