moving from house to an apartment.. goodbye 802D's

Did you consider a dipole subwoofer? It made a huge difference for my neighbors and I can now turn up the listening volume higher than before. You would get the added benefit of less boomy bass and more articulate bass than with a closed or ported sub.

Don’t get rid of your 802D‘s. If you love them definitely keep them. You don’t need to crank up the volume like a mad man and you can still enjoy music the way you are used to. Once you had a full size speaker there’s no way back to bookshelf little box.

Any speaker has potential to create issues.  .  
Surprised no one has mentioned getting absorption panels and very thick bass traps.  
Assume 802ds are all broken in, new speakers like young dogs need taming.  802s arely lovely.  Dont risk unhappiness by letting them go. 

IF you need to downsize - then downsize. That’s what the 805s are for. They are not lacking in bass but a sub would duplicate your 802 experience. Maybe the platforms underneath the 802 will get the job done. Maybe not. If the latter or you don’t want to experiment to find out, just follow the path B&W has laid out for you so clearly. The dirty little secret as well is the butyl rubber surround on the 805 cancels breakup distortion even better than the other D3 models. The ball's in your court.

Thanks John 
Much appreciated!