Spilled some beer on my laptop so couldn't share the progress as some buttons weren't working, but now we good to go.
To join two halves together I glued GF brackets to the top half, they will be held together with 6 M2 screws:

Cut some holes for ESC cooling:

As I mentioned I've no full sheet of PET for my vacuum box, so did the windows the old skool way. Using window off-cuts I sculpted forms from clay and with heatgun stretch around a piece of clear plastic. Looks a bit on a rough side but it has to do...