Is there anyone who could try and explain where water could possible be coming from to leak on to my speaker and in to my trunk.

 

your leak could be in 2 possible places. 1 is there is a break down in the seal that glues down the back glass (i had the same leak before) 2 is the tube for the sunroof run off could be clogged or damaged. It runs down the passenger side of the car to the rear wheel well.