The safe has 2 x holes at the bottom to fix it to the floor. The first hole is located towards the front of the unit near the door: 80 mm from the left hand side by 100 mm from the front. The second hole is located towards the back of the unit: 80 mm from the right hand side by 260 mm from the back. The hole diameter is 10 mm.

You are correct. This safe is supplied with a back up key so that it can be opened should the batteries fail.