I see you got the motor out. Just wanted to share out the information I found about this before I completed moving the motor to the trunk.
I just completed doing this although I can't come out an help you as I'm from the states. I put here a bunch of links I followed to do it. I compiled this list recently to help me through it. You will need 2 people, especially to lift out the convertible top. Follow tips like tape around the body near the top to protect it.
https://www.youtube.com/watch?v=8dWMaZv-WQ4
https://www.youtube.com/watch?v=O7lfvKerfhg&t=83s
A document on how to do it in which they discuss they sell 4" longer hoses to make it easier.
https://www.tophydraulicsinc.com/bmwz4instructions.pdf
A thread from a Z forum about doing it
https://www.zpost.com/forums/showthread.php?t=1215892
I also found a couple of documents. Search for through Google. This had the best document on how to do it. I cut the plastic a little closer to the location the motor sat in because it gave me a little more room to move around the motor. "Z4 E85 Top Motor Relocation (Revision 1).pdf" and "Z4 E85 Roadster Soft Top Lift Cylinder Replacement.pdf" I couldn't figure out how to attach them here but Google should be able to find them.
I did run into some issues like figuring out how to replace the bottom cover where the top fits in the trunk. Putting the plastic clips back in with little room for hands wasn't easy.
I may have to pull the top again because I don't think I have it sitting in properly. I'm not sure I have the aluminum frame properly in the u-clip and I'm gonna create a separate post about that once I take some pictures.
When I get a chance, I'll post some pictures. Good luck.