I apologise for the long quite, work has been hectic! I tried to use clr-boot-manager and it did not remove the screen.
However, I have uncovered something else that is worrying; the kernel number is frozen at 5.6.10 (uname and boot-screen) even after numerous OS updates, see the below:
uname -a
Linux lusi 5.6.10-947.native #1 SMP Sat May 2 11:03:57 PDT 2020 x86_64 GNU/Linux
swupd info
Distribution: Clear Linux OS
Installed version: 33620
clr-boot-manager list-kernels
- org.clearlinux.native.5.7.15-977
org.clearlinux.native.5.6.10-947
org.clearlinux.iot-lts2018-sos.4.19.128-109
org.clearlinux.iot-lts2018-sos.4.19.120-108
Even though I set the active kernel to 5.7.* it remains at 5.6.10*