Characteristics:

• the top line is an advertising slogan:TELEGRAPH! ..."
  It begins 21 mm after the C of COMMONWEALTH in line 2:
• The R of RECEIVED "line" below;
• the form has 4 sections for telegram details;
• there is a comment bordered by two lines and beginning "TELEGRAPH! ..." referring to advertisements on the reverse side;
• the four lines in the Remarks box are centered;

Reverse side of the Victoria Park telegram above showing the three advertisements used in this June printing.

Characteristics:

• no special heading;
• advertisements are not boxed;
• Advertisements start:
  "A traveller may find ..";
  "A TELEPHONE COSTS: ...";
  "THE PROMPT DELIVERY ...";
• all text is printed in pale blue;

Clearly a separate printing requiring at least an adjustment to the printing plate.
Also printed in June 1929.

Characteristics:

• the top three lines are the same in wording and placement across both forms;
• the 4th line is indented 27 mm in Form 6Aa and 23 m in Form 6Ab.
  This difference can be see in the placement of the R of Received over the word "line" below;
• there are other differences in alignment between 6Aa and 6Ab in the text at the base of the REMARKS box;

There is only one real variation between the reverse sides of 6Aa and 6Ab and that is the extra space between the heading and the message in the last column.

HOWEVER

there are differences within the printing of the reverse side of 6Ab:
some forms have a slightly smaller font size and these forms also have a small ornamental bow in the center column between the last two annotations.

Characteristics:
Has a different advertisement at the top:
For Quick Service Use the Telegraph.
This slogan was also used on the corresponding
Urgent rate delivery form (AB-DU-6).

Reverse side of the Perth telegram above showing the three new advertisements used in this October printing.
These same advertisements appeared on all the October 1929 forms.