I had this in mine so I went looking around in the boot and found the spare was a little loose as were a couple of the tools. After reseating the spare on its soundproofing mat stuff in the bottom of the wheel well and firmly pressing the loose tools into their clips and tightening the yellow plastic thing in the middle...no more squeaks/rattles, Ive also started going around the interior sticking those self-adhesive plastic pimples to stop the trim from rattling. Im after some narrow thin felt to stick around the edges of the dash cover and some of the side panels. I once had a Datsun 280ZX and this had foam everywhere as standard, there wasnt a single squeak or rattle from that car!
I also noticed, while looking around in the back that the seatbelt receptacles recessed into the seat cushions are a little loose and can be made to rattle and the lower edge of the door pillar trim is free to move about.
Hope this helps a little.