I took up Dan Egli's kind offer of offline help and with that, my XPS 8940 is now booting UEFI. Thanks Dan. I've logged in both at the physical keyboard and via ssh from my current desktop PC. There's still the usual grunt work setting up the regular user account and the usual applications, but that shouldn't be a problem... famous last words.
-- Walter Dnes <[email protected]> I don't run "desktop environments"; I run useful applications
