The inside one closest to the tunnel is PITA. A fine tooth ratchet is your best friend, but Can be done with a regular ratchet. Use a short 15mm socket, and 3/8" drive ratchet. Easiest thing to do is reach in around with your left hand and guide the socket onto the bolt head. And hold it on there while you use your right hand to function the ratchet. It will take a bit as you will only get short strokes of the ratchet.