Thank you joshuasamah.

Unfortunately, while I see styles similar at Grohe, none seem to have that primary feature I am looking for - the minimal backplate. Below is a similar design from Grohe, where you can see how the backplate is three times the size of the one from Sussex Taps.

I appreciate the attempt! Perhaps there is an option from Grohe I am missing?

Any other leads still welcome!

I have a Grohe lavatory faucet that is a good match for that one, but like you noted, the shower controls are quite different. The controls that are on the bar might work for you--even in your installed photo, there's so much going on with the shower head/bar thing, would you notice if there was also a control on it?

Did you try Dornbracht? Good luck!

Fori - the installed picture was meant to show what I was after for controls. My showerhead situation would be entirely different. Here is a different installed photo of the Sussex Tap with just a showerhead, no handhelds. As you can see, all the shower needs is the very discreet handle. That is what I am after. That very discreet handle, nothing else on the control wall.

Scottie mom - thank you for the suggestion! I found a Dornbracht option on QualityBath that I think might work. It also led me to an option from American Standard. It's hard to fully understand the terminology and know that I am looking at something that is fully workable as a single shower control, but I think it is. Obviously, all this would be run by the contractor and builder eventually, but I like to have all my research done and materials chosen before going into those meetings.

ETA: Alas, I don't think those above will work. They are only volume control, and cannot control temperature. While there are many single handle temperature plus volume controls out there, they all seem to have a larger backplate. I just don't get it. I know this isn't a strange item - you tilt the handle out to turn the water on as much as you want, and tilt it side to side to side to adjust temperature. So simple. So normal. So why does it require such a large backplate??

Ah. Glad you found the Dornbracht attractive at least! Thermostatic valve has a lot of guts to cover, so usually bigger, I suppose. But DB has some of the best minimal trims I’ve seen. Find a plumber who’s comfortable with German fixtures.

Try Vola for a similar look.

It's much better in that second installation! (Not much point in the first because the rest of the shower is so busy!)

Hansgrohe ShowerSelect S. I think it controls both the temperature (obviously) and volume but I'm not absolutely sure. The website description and datasheet are vague.