Hi Roy,
Your 'best price' is going to be relative;
What are you going to do with all the electrical equipment if you convert it back?
If you are going to use it on another lathe then you could convert back to manual as the cost of replacement has to be added to the cost of the lathe that you are going to connect it to.
If the CNC stuff is going to sit in a box under your bench for ever more and become obsolete before you (or the grandchildren) use it, then leave it attached and sell the whole thing complete.
Are you considering putting it up for auction or are you going to sell it for a fixed price? As a complete CNC'd machine or course you can ask a better price, but, as I asked above, at what cost to you?
Your choice…
Andy