S320 Limo - replacing window motor

Hi all,
A new memebr to the forum. I have owned a S320 Limo (1999 old shape) for the past 2 years and enjoy it very much.
A couple of months ago, my driver side window stopped going up and down, and i have had to push the double glazed glass up by hand. Every now and then it slides back down due to the shear weight of it. I have enquired on getting it fixed and the cost quoted have been £400 labour + parts. I am told I have to replace the motor!

I have purchased a motor from a breakers, and would like to replace it myself.
Hence why I am here asking anyone if they have had to replace it? I can not find any screws/fixing caps etc on the door panel and can not see how the panel may be removed??  

I have spent quite a lot of money on parts and labour over the 2 years, and can not afford to pay someone else to do anything, I could perhaps do myself!!

I would really appreciate anyone's help on this.
 
Thank you in advance.

there are 2 screws in the door armrest, under the hinges of the armrest/ pocket. then you must remove the wood trim by your grab handle in the door, its a sort of triangle shape wood trim( careful not to break the trim its $$$) and there is a special tool to take it out. then there is a screw under the  grabhandle,  door panel will have door clips around the perimeter of the door panel unpop them them slide panel up and out.

Thanks for the advice.
I was beginning to think no one could help.
As it happens, I braved it over the weekend and tried to remove the panel myself, which wasn't too difficult. The most difficult part was to remove the mechanism which carries the window.
Thanks