An unlikely title that many Malta collectors may have missed "Great Britain with Post Offices in Central and South America, Europe, Middle East, Asia and Australasia " saw a Maltese rarity go under the hammer :

Lot 208

Stamps of Great Britain Cancelled "M", 1857-59 embossed 6d. violet with good margins and clearly cancelled "M"; trivial wrinkle at right, otherwise fine.

Exceptionally rare. Sc. A20; S.G. Z19, Cat £4,250. 

Provenance: Leonard Hearn, 1960

Estimate £2500 to £3000

Sold for £3500 (plus fees)

There were other lots but nothing to mention