So I would like to know if I can essentially return Reaper back to default with none of the scripts I have added, so it goes back to what it was when I first downloaded it. Like a reset, without uninstalling it and re downloading Many thanks Dan

Delete the resource folder (or move it somewhere else so you have a backup just in case). This is where all settings and scripts are stored. REAPER will create a fresh one the next time it's started. Options > Show REAPER resource path in explorer/finder

Just install Reaper again, but this time as portable?

I usually have to test scripts in default installations. One time I tried to work on a project with this portable default installation. I was completely unable to work at all. It is amazing how you get used to your customizations and then you cannot work with anything else :) or at least me. I believe that is the power of REAPER.