Frim your photo, i would guess that your rose is a semi-double. It might be helpful to count the petals on a few individual blooms sometime. Perhaps your rose may not be ‘Excellence von Schubert’ because the earliest reference (1909-93) said the flowers of ‘Excellence von Schubert’ were the size and structure of the carmine pink ‘Gloire des Polyanthas’. That (GdP) was a double flower.

It is more likely that your rose, and probably most in Australia, may be ‘Gartendirektor Otto Linne’ but we really need more information on this rose. HelpMeFind at the moment are listing it as double. The 1936 Hazlewood reference is of interest - did they import something else?
Look closely at the foliage. ‘Gartendirektor Otto Linne’s offspring, bred by Riethmuller: ‘Carabella’ and ‘Honeyflow’ and ‘Gay Vista’ have the same leaves as shown in Eric Timewells photo of the ‘GOL’ plant from Trewallyn Nursery.

A little more on others in Australia. Please see my photo captioned
“ROSE SOLD IN AUSTRALIA AS 'Excellenz von Schubert' accompanying an article written by Merv Trimper in the May, 2001 'Your Garden' magazine. The semi-double rose pictured, may (or may not be) 'Gartendirektor Otto Linne'. It does not appear to be the double 'Excellenz von Schubert' as grown in America.”

I received a cutting from a friend of Merv Trimper’s rose in 2013. This was planted at Ult-half-N-67 and is the same as the photo, mentioned above, with lots of white streaks. I have wondered if it is infected with petal fleck disease. However, as I believe petal fleck is only transmitted by cuttings, I have never worried about it in my garden, just never shared it around. . (To play it safe however I have never deadheaded it and, Margaret Furness, you asked once about hips and this plant is setting hips.) Margaret Furness’ photo of Thomas for Roses ‘Excellence von Schubert, appears to be the same rose.

This bush and bloom is exactly the same as the one which came as Excellence von Schubert’ from Ken McAlpine-1; Wal Johnson-2; (without the white fleck) in the same 2013 year and planted at Ult-half-S-57.

So, two identical semi-double roses planted with three metres of each other, both named ‘Excellence von Schubert’ No. 67 with white streaks, and No 57 without. There is some repeat on both bushes.