[brazen1]

Assuming your 3D.iso's are complete rips, you need a player that renders menus like PowerDVD.  I know of no others.  Check eBay.  Many are unloading the older version which isn't much different from the newer at VERY attractive prices as is DVDFab player - excellent for UHD HDR also with menus but no 3D.  Neither DSPlayer nor MPC are menu capable or iso friendly.  However, once mounted, they can render the main movie only from a full complete iso rip.  To do this, the iso needs to be mounted in some fashion.  For MPC players, you call a .bat to do the mounting and the stereoscopic enabling when using NVidia.  AMD apparently does need to enable stereoscopic but a .bat associated with that GPU also needs to mount an iso for players to read as does Intel Graphics.  You need to distinguish a 3D title from all others, including iso's even though your 3D titles are also iso's, and assign MPC-BE to play them.  Assuming your Play3D.bat is correct (mounts and enables stereoscopic if needed and calls MPC-BE as the player) AND .3D is in the filename of all your 3D titles, simply remove iso from your code and use this:

<playercorefactory>
 <players>
< player name="MPC" type="ExternalPlayer" audio="false" video="true">
       <filename>C:\Users\Dave\AppData\Roaming\Kodi\userdata\Play3D.bat</filename>
       <args>"{1}"</args>
       <hidekodi>true</hidekodi>
       <hideconsole>true</hideconsole>
       <forceontop>false</forceontop>
       <playcountminimumtime>1140</playcountminimumtime>
    </player>
    </players>
 <rules action="prepend">
  <rule filename="*.3D*" player="MPC"/>
 </rules>
< /playercorefactory>

Fwiw, you really don't need any of this depending what you are doing:

<args>"{1}"</args>
       <hidekodi>true</hidekodi>
       <hideconsole>true</hideconsole>
       <forceontop>false</forceontop>