Lost all my custom keyboard shortcuts So I think I accidentally deleted my shortcut presets by a mis click and can't get them back.

I believe I had a custom preset name and I accidentally clicked '-', which immediately deleted my custom presets and set them back to default.

All the keyboard shortcuts I carefully set over the months / years are gone.

I thought I had been saving the shortcuts when I clicked "Save User Settings" in the user preferences file. Unfortunately this does not appear to be the case. I backed up both that file and the startup.blend file. Unfortunately loading startup does not have the shortcuts either.

Am I fated to go through and redefine all the shortcuts again? I suppose everything is a learning experience..
My guess is that you just upgraded Blender, and didn't click 'Copy Previous Settings' in the splash screen. This would copy your settings of 2.78 to 2.79; without this, Blender uses the defaults after an upgrade.

If you haven't saved new settings yet, the 'Copy Previous Settings' button will still be available in the splash screen. If you want to remove your 2.79 settings, you have to visit a platform-dependent path. These paths are documented in the Blender Manual.