This is a series of cards printed on unusually thick, unbleached card.  They were published during or just after the end of WW2, so there may have been a shortage of better quality card.  They were printed by halftone.

The cards are not identified as being by Valentines.  They have a caption and numbering in the form  "Series nnnn", eg Series 4408.  The number is the card number from the Real Photo Series, where cards were identified in a form as "Valentine Series 4408", but the word "Valentine" has been omitted and the plural "Series" retained.
 

Series Contents: The images seem to be the same as for the Real Photo Series. How many of them were reprinted in this series is not known.

Date Published:  The earliest date I have seen is 23/4/46, in correspondence on the "Burnie showing Round Hill" card.
 

Printing: These cards were printed by halftone, most likely in Australia.

Identification: Recognisable by the thick card and the halftone printing.