When I start the car it doesn't make an odd noise, just a normal noise like it always does. Then when I want to move it I put it in D and when I give gass to advance the car makes a noise that you can compare with giving to much gass and then the car starts moving so it doesn't move immeadialty as it is supposed to when you put it in D. When I'm driving the car in D there is no noise it's only when I stop and move again that there's the same noise and the delay in movement as when I've just put it in D. When I put the transmission in R it moves forwards without any noise (just like it is supposed to do in D).
Ok,,ive narrowed it down to three main cause which are all connected to your issue, now the main point to consider here is that your gearbox components will require to be replaced and not the gearbox itself, any company that tells you the transmission has failed doesnt know abouth the BMW X5 gearbox, as all they will do is refurb the stator and bull ring and install a new one way clutch and or stator and torque convertor.
Now from your description my guess without seeing the car is that the one way clutch and stator is at fault, basically the stator's job is to redirect the fluid returning from the torque converter in an opposite direction, now if this does not happen then a mix up of gears occurs, basically you might have a build up of trans fluid from the turbine part of the torque converter which the stator is suppose to redirect,,now in common issues the stator fails, thus leads to one way clutch failure and the torque converter spins and spins until it can find engagement to drive forward, so in theory your one way clutch and stator need to be checked out along with new trans fluid, a cost for a one way clutch and sator kit is roughly £ 700, to take the gearbox out is 4 hours, to refit the parts is 2 hours, then refit the gearbox, im pretty positive that this is what is causing your issue,,for a garage to charge you for this work,,,,id pay no more than £1600,and your car will drive like a dream.
Hope this is of help to you,,,,,,,