During may 1903 a new design of Gibraltar stamps was issued and placed on sale in the Post Office of Gibraltar. They bore the head of the new sovereign, H.M. King Edward VII. All the issues was watermarked with the Single Crown C.A., and perf. 14, and all the values were printed from Plate 1 only.

The 1/2 to 1s. were printed in sheets of 120 in two panes of 60; the other values in sheets of 60 in six row of ten. The higher values are considered from an artistic point of view as the most handsome of all the then new King's Head issues. Their colours too are worthy of the highest praise as being a step forward freshness and harmony.

Only one printing was made of these stamps on Single Crown C.A. paper and so they are scarce. Each value was replaced as the stock in hand was exhausted, by the series on Multiple Crown C.A. paper in the same colours, with the exception of the 8s. which lasted until the appearance of the Universal Colours Series. It was therefore never printed in these, its original colours, on Multiple Crown C.A. paper. The 4d. value was omitted from these Edwardian issues as being found unnecessary. 

The subsequent changes in the watermark and colours of these designs make the issues scarce.

Gibraltar Stamps: King Edward VII 1904-1908. Wmk Mult Crown CA. P 14.

Between June 1904 and June 1908 the preceding issue appeared on Multiple Crown C.A. Wmk. Mr. Douglas B. Armstrong, in the “ Philatelic Magazine ” of May 20th, 1920, gives the following dates of the six values concerned printed on ordinary unsurfaced paper with the Multiple Crown C.A. Wmk. He mentions the fact that the printing of the sheets of the low value stamps in this issue was reduced to two horizontal panes of 60 in view of an accident to the key plate. This list is now subjoined.

The 1d. denomination printed on surface coated paper was issued on September 16th, 1905, and was one of the first British Colonial postage and revenue stamps to appear in this form as the singly fugitive colours of Messrs. De La Rue & Co., were not found to be quite a sufficient safeguard in the case where stamps were used for fiscal purposes as well as for postage. The paper for the stamps of Great Britain as well as for the Colonies was gradually superseded by a chalk surfaced paper which rendered any attempt to remove obliterations impossible. All values were issued on the chalky paper. The 21/2d., on chalky paper, was issued for a very short time and is consequently scarce. It is stated by Mr. Armstrong that only 24,000 of these stamps were issued. The dates of issue are given by him as follows:

Those values marked ( * ) are found in well-defined different shades.

The ?1 Multiple Crown and C. A., in this issue, and the preceding one — Crown and C.A. — are especially scarce as they were issued before the days of highly developed stamp collecting.

The 21/2d., 4s. and ?1 are printed on the chalky paper only, whilst the other values are found on the two varieties of paper.

Gibraltar SG 64 ?1 stamp used on piece

Large "2" in "1/2" variety of 21/2 penny King Edward VII Gibraltar stamps

There is a variety of the 21/2d. value. In the 55th and the 115th stamp of each pane respectively the “2” in the fraction “1/2” is somewhat larger. This variety is known as the “ large 2 ” in “ half”.

Gibraltar SG 49 Two and halfpenny stamps in block of 4 from
the lower left corner of the right pane. One stamp with variety
large ''2'' in ''1/2'' [R. 10/1], SG. 49a. Sold at Grosvenor Auction
in 2009 for ?230 plus buyer's premium

Gibraltar SG 59 Two and halfpenny stamps in block of 4
from the lower left corner of the left pane with plate No. 1.
One stamp with variety large ''2'' in ''1/2'' [R. 10/1], SG. 59a.
Sold at Grosvenor Auction in 2009 for ?480 plus buyer's premium

Gibraltar Postal History with King Edward VII stamps

Gibraltar Postal History: KEVII 1903 8s stamp used with 1906-12
2s. and 4s. on registered ''Kinze'' cover to Germany, tied by
''12 SE 10'' oval datestamps with transits and Sept. 18 arrival
on reverse. SG. 54, 72, 73. Sold at Grosvenor Auction in 2006
for ?230 plus buyer's premium

References:

1. "The Postage Stamps of Gibraltar" by Geoffrey E. Duveen, First Edition 1932, Reprint 1972.