A tricky install.
Previously I had been using the RadeonDeInit=true key instead of Whatevergreen for my RX560, but for this update that just resulted in a loss of video signal, so the kext had to be installed.
Also tried Clover 2.4 r4895 but that seemed to stall the process.
After a lot of to-ing and fro-ing the proper way forward had to be:
install latest Clover from
here (4862) and also the latest Lilu and Whatevergreen kexts (1.3.5 & 1.2.7). Remove the RadeonDeInit key.
Subsequently a smooth install.
Of note now is the longer pause between APFS init and Clover drive menu. Used to be say, 2-seconds, now 7-seconds.
EDIT: The longer delay mentioned above has been identified. From what I read it's common for Boot Debug to be defaulted to "true" for some Clover updates, however that wasn't the problem here.
The cause was a new file in the drivers64UEFI sub-folder called "AudioDxe-64.efi"
This wasn't present previously and I watched it be installed by the newer version of Clover. Knowing my audio worked previously I decided to remove it (to a safe place just in case) and reboot.
The problem was gone.