[Radio Wrangler]

Looking at the photos, the first one seems to have a different socket box to the others.

That auction seems to have some rather attractive stuff. The headset testers, pressure testers, sound level meters and the angular position stuff make me think it's a clearout from some military/aerospace outfit.

The HP spectrum analysers E440x are known as the 'Mosquito' project. LCD and more up to date, but designed as the economy family. They work well and have more modern interfaces than earlier families. Of course, to know what's actually in the box, you need to see the listing of fitted options.

The HP 856xE series spectrum analysers are the high performance family of a generation earlier. Well known, quite capable. The E on the end marks them out as having updated processors and a card cage for option boards. Again you need to know the fitted options to know just what you're getting. 6x analysers seem to go for around £2k at Stewart of Reading, but that includes the 22GHz variants. These are portable versions and descendants of the legendary HP8566 "Doomsday Box" project.
These use CRTs and not just that electrostatic scope-type CRTs. Known to dim and defocus with age and absolutely irreplaceable. There are some kits from vendors in the US to do an LCD replacement, but they are very expensive. With an E, you can always suck trace data to a computer and view it there even if there is no functional CRT. (The very last versions of this family did switch to a colour LCD, but they are rather rare)

The distortion meters are classic old-school HP. Lovely inside. Reasonable performance. Rock solid construction and very reliable taut-band movements in the meters (likely platinum).

The most of the HP 5400 series oscilloscopes were subsamplers. Most ran at 20 MS/s and sometimes split that between two channels. They'll only reach their headline MHz on repetitive signals. Very much dated and not as useable as modern ones.

David