A modern classic with its graceful simple design and recess printing process. Four beautiful stamps selected after much consideration which have proved very popular with collectors dealers judges exhibitors alike and that can't be said for many issues !! Proofs are very rare but are occasionally offered and photographic bromides with  providence are quite acceptable. The issue has some fine but scarce printing errors and inverted watermarks, 'confetti' flaws, misperfs and the like are eagerly bought and sold. The great emerging collecting area is for commercially used covers/usages ( as distinct from philatelic inspired first day covers) and you try and find a 10/- or £1 paying the correct rate !! A  source of very attractive usages are the parcel tags - offering high value attractive combinations.