All we know of her is her forenames and that she was born around 1873 in Newcastle upon Tyne.

In 1901 she was ‘Barbara D’; in 1911 she was ‘Dolores Barbara’.

This is all that turns up on FindMyPast that might be her birth:

Name:                      Mother's Maiden Surname:
WILSON, ADELAIDE DOLORAS   JURY  
GRO Reference: 1873  S Quarter in SOUTH SHIELDS  Volume 10A  Page 769

Some other evidence might confirm this, e.g. her maiden name on the birth registration of their son.

But the maiden name given is Nicholson, so the above is wrong!  And no Dolores Barbara Nicholson birth can be found.
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I then searched for all Nicholsons in the 1881 and 1891 censuses in the Newcastle area plus 20 miles around it born between 1870 and 1874 to see if she could be found:

There were but two such:

In 1881 only a Barbara born in

In 1881 and 1891 a Frances B born in Morpeth whom the new Birth indices show to be a Frances Bates Nicholson, so not Barbara.  In both census she was living with her grandmother.

In 1881 only a Barbara Nicholson born in 1870, living in Gateshead.  Not found though there was a Barbara Nicholson born in 1868 who was born in Newcastle upon Tyne

But there are no people that look like one who might haver been Dolores Barbara in 1911.
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A few birth statistics for female Nicholsons with NO forenames, from 1880 to 1884 in registration districts around Newcastle upon Tyne, from the new GRO site:

1. There are 66 Nicholason births in Newcastlye upon Tyne, none with any named Dolores or Barbara,
2. There are no births at all in North Tyneside, (did that district not exist then?),
3. There are none in South Tyneside,
4. There are 52 in Tynemouth, of which none resemble Barbara or Dolores,
5. There are no births in North Shields
6. There 33 in South Shields none with any Dolores or Barbara in their names,
7. There is one Barbara Harrison Nicholson in Co Durham,
8. There are 2 births in Alnwick but none with any Dolores or Barbara in their names,
9. There are 7 births in Castle Ward but none with any Dolores or Barbara in their names,
10.There are 22 births in Morpeth but none with any Dolores or Barbara in their names,
11.There are 30 births in Sunderland and of these one was Barbara Nicholson,
12.There are 8 births in Houghton le Spring but none with any Dolores or Barbara in their names,
13.There are 41 births in Gateshead but none with any Dolores or Barbara in their names,
14.There are 18 birth in Chester Le Street but none with any Dolores or Barbara in their names.

I conclude that Dolores Barbara is a mystery and either her parents did not register her birth or she was trying to conceal something.  IF the latter, then her other information, such as her forenames and maiden name could all be suspect.
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Ancestry has this for her death:

Name:                 Dolores Barbara Park
Birth Year:           abt 1875
Age:                  58
Death Place:          Pran, Victoria
Registration Year:    1933
Registration Place:   Victoria
Registration Number:  2650
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And the Victoria record office at <https://my.rio.bdm.vic.gov.au>; has:

                        Mother's  Mother's
                        name /    family            
Family  Given           Spouse's  name      Father's  Place of  Place of  Spouse    Age at  Reg
name    name(s)  Event  name      at birth  name      birth     death     at death  Death   number

PARK    Dolores  Death  <Unknown  <Un-      <un-      <un-      PRAHRAN   <un-       68     2650/
        Barbara          Family    known>    known>    known>              known>           1933
                         Name>
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