I finally got up the nerve to do a kernel update of my PCLINUXOS system. I made sure I had a good backup of all of my files before starting. Actually I made two as I tend to be a bit paranoid about such things.
The process is very easy. I launched Synaptic and then did a search for 'Kernel'. I selected the kernel I wanted and then let it install. For the first several weeks I kept the default kernel and manually switched to the new one. Once I was happy I then used the Control centre to change what the default kernel was.
I selected the new kernel that I want to change the defaults on.
I then clicked on 'Default' to make this the new default.
The image is what KDE shows. It took me about 15 minutes to add the kernel and then later to change the default kernel that the system boots to. Just remember to make a good set up backups before trying this.