To reove the back seat from a Mazda 6, you need to do the following.
1. Remove the 4 plastic covers on the front edge of the seat. You can prise them off easily.
2. Removing these covers exposes 4 10mm bolts, which have to be removed.
3. Now, you will be able to raise the base of the seat, and this will allow you to see 4 13mm bolts, which have to come out.
4. You will need a fairly large size Torx to undo the seat belt anchorages. The reason for this is, that the seatbelts are built into the seats, and so need to be undone.
5. Uncover the bolts behind the seat by pulling the carpet away. The carpet is secured by some push type clips, which pull out easily.
6. Undo the 4 13mm bolts behind the seat.
7. When you have all the bolts undone, the only thing holding the seat is the cable mechanism for allowing the seat to tilt forward. Prise the little black cover open, and remove the cable. (cable remains attached to the seat)
8. You're done!!