Well I thought this was going to be an easy fix!!!!
I have taken the centre speaker grill out and still get the rattle, removed the centre speaker and pulled the harness tight and still get the rattle, strange thing is when everything is back together and I drive the car and I get the rattle by applying the slightest of pressure to the speaker grill the rattle stops? It also seems temperature related.
I tried to pull the dash towards me and that seems fine. Contacted Lexus Birmingham and they want £65 just to assess the problem.