On 26 April 1948, The King and The Queen celebrated their 25th Wedding Anniversary. It was honoured in the Commonwealth with this set of Omnibus stamps:

The lower value of the sets was lithographed and are affordable. The higher value is engraved and is considerably more expensive.
As the high values were higher than normal values (i.e. 10/-, $10, etc.) other than on First Day Covers and those few used on parcels that did not get a heavy postmark, finding nice used examples is difficult. These high values are rarely discounted.
This one crossed my desk on Friday and Ian sold it to me at a good deal. I love my job!

The postmark, on this 10/- is neither philatelic nor favour.
In my opinion, this set is the most beautiful of the Omnibus Series of stamps, by Crown Agents, of the Reign.
David