How to get Nvidia drivers working on HP ZBook with Ubuntu 20.04?

I have a “HP ZBook 15v G5” which I’m trying to get the “recommended” Nvidia graphics drivers working with.

Running the following suggests nvidia-driver-455 are the recommended ones:

➜  ~ ubuntu-drivers devices           
== /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0 ==
modalias : pci:v000010DEd00001CBCsv0000103Csd0000847Bbc03sc00i00
vendor   : NVIDIA Corporation
model    : GP107GLM (Quadro P600 Mobile)
driver   : nvidia-driver-390 - distro non-free
driver   : nvidia-driver-418-server - distro non-free
driver   : nvidia-driver-455 - third-party free recommended
driver   : nvidia-driver-440-server - distro non-free
driver   : nvidia-driver-450-server - distro non-free
driver   : nvidia-driver-450 - distro non-free
driver   : xserver-xorg-video-nouveau - distro free builtin

But when I try to install them automatically I get:

➜  ~ sudo ubuntu-drivers autoinstall            
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies.
 linux-modules-nvidia-455-generic-hwe-20.04 : Depends: nvidia-kernel-common-455 (<= 455.38-1) but 455.45.01-0ubuntu0.20.04.1 is to be installed
E: Unable to correct problems, you have held broken packages.

Not sure if it’s worth noting I did upgrade from Ubuntu 18.04 but hadn’t got them working on that either.

Apologies if this is obvious, don’t have much experience with graphics drivers on Ubuntu yet.

Appears I’m using the Nouveau display drivers at the moment, and I’m trying to update them to the Nvidia ones because occasionally my second monitor will go black for 10 or 15 seconds when switching applications, and then come back again:
Drivers Screen