I have just bought a P-reg Polo sedan and like a numpty

I left the sidelights on all night and completely flattened the battery. I jump started the car the next day, but since then, when I turn on the ignition the code
IN 02 appears on the odometer. It starts and runs fine and was not long since serviced. So after all this waffle my question is...
Does anyone know how to reset this code?
Thanks for any advice other than "It needs a service"
FunkyKex