Horning Eufrodites - help needed with boomy bass

Amuseb, have you had the problem from day one? Lots of interesting suggestions, but maybe this isn't the spkr for your room, period?
I used to run Zu Definitions Mk2s, with xoverless full range drivers and 4 x 10" bass drivers out the rear, so some major similarities with your Hornings. Bass integration was a major issue, and I mostly solved it using the Spatial Computer Black Hole anti-bass wave generator, which sitting behind the listener, uses a mic and dsp to sample the bass from the main spkrs, and pumps bass into the room to eliminate phase issues, standing waves and bass nodes. The problem wasn't totally solved, but improved a good 60-70%.
I've upgraded to the Zu Definitions 4s which dispense with rear firing woofers for a single floor firing one. Bass better than ever, but still helped by the Black Hole.
For $1250, full money back guarantee, it's worth a try.

I used to run Zu Definitions 2 spkrs with xoverless full range drivers and 4 x 10" rear firing woofers per spkr, ie many similarities to your Hornings. Always found bass had a tendency to boom and overpower the room. My solution which was c80% effective? Installing a Spatial Computer Black hole anti-bass wave generator. This is in effect a one cubic foot subwoofer sited behind/alongside the listener next to a wall, with integral mic which samples the bass put out by the main spkrs; via dsp, it puts out a cancelling wave of bass, so dealing with standing waves and bass nodes.
Bass hash/boom was much improved, with subsequent improvement in intelligibility, transparency and dynamics.
At $1300 with a full money back guarantee if not happy, you can't go wrong. Clayton Shaw who runs the company is one of the good guys in audio.

Amuseb, are you really sure you can't site a diminutive 12"x12"x12" sub behind you, with one power cable? You could even put a vase of flowers on top to obscure it (max WAF!).
It REALLY solved my boomy bass issues, and maybe more than other contributors here, my prev spkrs are probably as close to yours, and hence experience similar, so I know where you're coming from more than most.
Clayton offers full money back if it doesn't solve your needs. Worth a try, surely?

You're right, no free trial outside US. I live in London, England, and actually took a risk which paid off.
Beyond this unit, no other room treatments, other than a woolen rug on my wooden floor between me and the spkrs.