Mail to Australia - correctly paid in 1990 but underpaid in 1970.

Reader MikeM has sent two examples of mail to Australia.  The 1970 letter is underpaid, the 1990 postcard properly paid but with an unusual postmark.

Starting with the postcard.  29p paid the worldwide airmail postcard from 2 October 1989 to 16 September 1990 when it rose to 31p.  For the collector of 'solo use' this is the obvious way to find them. 

29p Machin solo use on airmail postcard to Australia 25 May 1990.

The original deep mauve stamp was issued in 26 September 1989 in sheets printed by Harrisons on phosphor paper (SG X979).   It was also printed in booklets of 4, in litho by Walsall, and issued on the date the rate came into force, 2 October 1989.  These litho printings are quite distinctive, not least because the stamps have two phosphor bands and the booklet pane is imperforate on three sides.  These (SG X1054) should not be difficult to find.

Although these booklets were available from most post offices they were also sold by tourist destinations in addition to the domestic rate booklets.  Having one worldwide rate meant that they only had one airmail booklet to stock.   

The booklet was reprinted on phosphor paper and issued on 17 April 1990 with imperforate edges as before (SG X1055).  This is probably more difficult to find due to its shorter usage period.

From 17 September 1990 the 29p stamp paid the under 10gr airmail rate for Printed Papers to Zones A and B (basically the whole world outside Europe excluding Australasia and the far east of Asia.  I suspect these are much more difficult to find.

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Mike's other piece is pre-decimal, a 1970 letter also to Australia, bearing the rarely seen 2 x 10d stone stamps, SG 741.  The potential problem here is that 2 x 10d = 1s 8d, and the correct rate was 1s 9d. evidently the Post Office didn't take the time to surcharge this international item for 1d, but they were not slow to do so for domestic mail.

Pair of 10d drab stamps on Airmail letter to Australia, May 1970, underpaying the 1s 9d rate by 1d.

The question which will never be answered is why were the 10d stamps used at all?  I don't think it was because the writer used them for an 8 ounce inland letter in July1968 when issued, or for a 10 ounce second class letter after the introduction of two-tier post from 16 September 1968. 

Much more likely is that they had some for sending airmail postcards to Australia, as 10d was the rate from 3 October 1966 to decimalisation on 15 February 1971. 

Or perhaps the sender was a collector, using a variety of stamps on different letters?  Whatever the circumstances they got the rate wrong! 

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