What year/model? If it's a 453 the battery is under the front hood. Earlier models have the battery under the floor in the passenger compartment. There are no external connections to jump start the car.
Is “flat battery “ = DEAD battery?Not the 12volt outlet, the thing that you used to plug in a cigarette lighter to that is now for cell phone chargers ( sorry I am a girl) The gismo has two identical connectors, one goes into the outlet of the car without the flat battery and the other goes into the one that has the flat battery.
You can unlock the the car. Emergency key slot under drivers side door handle. My wife ran the battery down once. Left the head lamps on. I used the key slot to open the drivers side door. That safety feature, are on all modern cars. If that key slot is blocked up, time to call a lock smith, slim Jim the door open.That would be handy, if the OP could unlock the car.
The greyed out picture is from the 451 owners manual. No idea what model the OP actually has.I still think it's a 451 by the greyed out dash picture. I also am not a Matlock or Sherlock Holmes... Would be interesting to find out what the remedy was though.