Ah, when it mentioned '7th character' I thought it was referring to the actual string given from the data array, not the driving license string I was building. Apologies.

In the java description:
"7–8: The month of birth (7th character incremented by 5 if driver is female i.e. 51–62 instead of 01–12)"

It should be incremented by 50, not 5. I was stuck on this for quite a while.

Probably needs some indents...