Cannot install cuDNN 11.7 on Ubuntu 22.04, shows "The public CUDA GPG key does not appear to be installed"

Good evening all,

Apologies for posting this, as I can see others have had the same issue but none of the suggestions are working for me.

I am at the following stage:

$ sudo dpkg -i cuda-repo-ubuntu2204-11-7-local_11.7.1-515.65.01-1_amd64.deb
(Reading database … 174906 files and directories currently installed.)
Preparing to unpack cuda-repo-ubuntu2204-11-7-local_11.7.1-515.65.01-1_amd64.deb …
Unpacking cuda-repo-ubuntu2204-11-7-local (11.7.1-515.65.01-1) over (11.7.1-515.65.01-1) …
Setting up cuda-repo-ubuntu2204-11-7-local (11.7.1-515.65.01-1) …

The public CUDA GPG key does not appear to be installed.
To install the key, run this command:
sudo cp /var/cuda-repo-ubuntu2204-11-7-local/cuda-F83D2C4C-keyring.gpg /usr/share/keyrings/

I get to this stage and run the last command:

sudo cp /var/cuda-repo-ubuntu2204-11-7-local/cuda-F83D2C4C-keyring.gpg /usr/share/keyrings/

And nothing happens. Please can anyone assist?