Help with Shower head connector without removing?

[Andrew32]

Morning,
I have this old shower head in a newly acquired house, and am trying to find a replacement shower head. Doesn't need to be the same design, but just trying to make sure the connector is the same as a new one.
I found an identical head online:
Amazon productBut in one question the answer is its 7/8" connector
Someone else states its 1/2" standard
recommended items include a 3/4" to 1/2" adapter?

Photos of my shower head linked here (yes its disgusting, way worse than it was, cleaning it caused it to break. great.)

Old shower head

0 new photos added to shared album

photos.app.goo.gl

 

[Aquarius]

I take it there’s no markings on shower unit or handles to determine what make/model shower?

 

[Shower Engineer]

That looks like a Bristan head to me. Unscrew the head by placing a spanner on the flat part showing below, another flat is on the other side! You should find a 1/2" male thread. No problem finding a head to suit that.