See if you can squeeze a thin spanner in between the tank and the black frame. I think a 17mm will fit. If it's the bolts at the top back then you have a problem.. My friend ruined his by turning around those... But I have a feeling that you are talking about the middle ones on the side no?
Put a T wrench on both sides, one will loosen, then pull one side out and you will see a flat spot on both sides of the tube, you can fit a spanner on this and T wrench the other bolt out.