Gfilui

I was following the discussion on this bug report;
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1728244

And the solution was applying a patched kernel from;
https://people.canonical.com/~khfeng/lp1728244-testing/

Now, I'm not sure which files I should be using or how I can apply them. Can someone help please?

First, make sure that your system it set so that the grub menu shows during boot and for long enough that you have time to select which kernel to boot. Typically, I use GRUB_TIMEOUT=20.

Download all 5 files into some temporary directory. Then execute:

sudo dpkg -i *.deb

Then re-boot and during boot, select the test kernel.
If you are not using grub, then I don't know.

Eventually, you will want to delete the test kernel. To do so, you must be booted to another kernel, not the test version (i.e. you can not delete the currently running kernel). You can use the excellent utility from here, or do it manually. While I only ever use the server version of the utility, I'll show the manual method:

doug@s15:~$ dpkg -l | grep 4.17.0-1
ii linux-headers-4.17.0-1 4.17.0-1.2~lp1728244 all Header files related to Linux kernel version 4.17.0
ii linux-headers-4.17.0-1-generic 4.17.0-1.2~lp1728244 amd64 Linux kernel headers for version 4.17.0 on 64 bit x86 SMP
ii linux-image-unsigned-4.17.0-1-generic 4.17.0-1.2~lp1728244 amd64 Linux kernel image for version 4.17.0 on 64 bit x86 SMP
ii linux-modules-4.17.0-1-generic 4.17.0-1.2~lp1728244 amd64 Linux kernel extra modules for version 4.17.0 on 64 bit x86 SMP
ii linux-modules-extra-4.17.0-1-generic 4.17.0-1.2~lp1728244 amd64 Linux kernel extra modules for version 4.17.0 on 64 bit x86 SMP
doug@s15:~$
doug@s15:~$ sudo dpkg -P linux-modules-extra-4.17.0-1-generic linux-modules-4.17.0-1-generic linux-image-unsigned-4.17.0-1-generic linux-headers-4.17.0-1-generic linux-headers-4.17.0-1
(Reading database ... 1480661 files and directories currently installed.)
Removing linux-modules-extra-4.17.0-1-generic (4.17.0-1.2~lp1728244) ...
...[deleted a bunch of lines]...
rmdir: failed to remove '/lib/modules/4.17.0-1-generic': Directory not empty
...

Notice that I reversed the purge list, so as not to get into dependency issues.
The directory thing seems to occur with 4.17 kernels, but the directory has a sub-directory which I guess confuses things. However, on my system it is gone anyhow.