I just tried to install KDE Neon 5.18 and after manually arranging the partitions (I wanted to keep my /home partition) and allocating 1000mb for EFI, the install proceeded normally but after removing the thumbdrive and pressing enter I get the following message:

System BootOrder not found. Initializing defaults.
Creating boot entry "Boot0003" with label "ubuntu" for file "\EFI\neon\shimx64.efi"
Restart System
(It might be \shlnx64.efi at the end -- I took a quick photo with my phone and it wasn't that clear).

It then just goes into an endless loop as it tries to reboot.
I'm using KDE Neon 5.18 'live' from the thumbdrive at the moment.
Any help or pointers would be appreciated.
Nigel

Update:
Finally managed to install KDE Neon
The solution was to ignore EFI altogether. My laptop is a 4 year old Lenovo with MBR BIOS and so during the [manual] install I formatted the existing fat 32 efi partition to ext 4 and made it /boot
Clicking 'Next' I got a message declaring that I had to go back and create an efi partition or to continue at my own risk with the possibility of it not booting. I continued. Finished to install and removed the disk on key and booted successfully into KDE Neon 5.18

Must be that efi is for newer computers with the new GPT and MBR is for older legacy computers with BIOS

Anyway, I hope this helps somebody else.