1961 POSB 3d, Timson printing, vertical strip of ten from the top left corner of the sheet, showing variety 'ORANGE-BROWN COMPLETELY OMITTED ON SIXTH STAMP AND PARTIAL OMISSIONS ON 5TH, 7TH AND 8TH STAMPS'; fine unmounted mint. SG 624Aa | Estimate - £400-£500 (Image)

1964 Forth Road Bridge 6d, vertical strip of nine from the top left corner of the sheet, showing variety 'LIGHT BLUE COMPLETELY OMITTED ON LOWER STAMP AND PARTIAL OMISSIONS ON 7TH AND 8TH STAMPS'; fine unmounted mint. Spectacular. SG 660a | Estimate - £2500-£3000 (Image)

1965 Lister Centenary 4d (Ordinary) vertical pair with top stamp showing ERROR BROWN-RED (TUBE) OMITTED, with normal stamp below, full unmounted o.g., very fine. SG 667a | Estimate - £200-£250 (Image)

1966 World Cup 6d top marginal block of six showing error black omitted, fine unmounted o.g., very fine, offered with normal single for comparison. SG 694a | Estimate - £400-£500 (Image)

1967-70 1d light olive, two phosphor bands, vertical strip of three showing spectacular inking flaw probably caused by cleaning solvent dropped on the printing plate. Fine unmounted mint. SG 724 var | Estimate - £100-£120 (Image)

1969 Concorde 1s6d deep blue, silver-grey and light blue unmounted mint selection including 'SILVER-GREY OMITTED' (2, one on first day envelope), 'SILVER-GREY SHIFTS' (2). Fine to very fine. SG 786a/y | Estimate - £300-£400 (Image)

1969 Machin 5s crimson-lake, left marginal block of twenty, one stamp with striking variety 'CONFETTI FLAW ON QUEEN'S FOREHEAD' (R5/2). Fine unmounted mint and most unusual on this issue. SG 788 var | Estimate - £100-£120 (Image)

1971 Anniversaries (4th series) 3p 'British Legion' showing error red-orange (Nurse's cloak) omitted, fine unmounted o.g., offered with normal for comparison. SG 887b | Estimate - £200-£250 (Image)

1971 Anniversaries 9p Rugby Football, upper left corner block of nine showing spectacular variety 'SHIFT OF OLIVE-BROWN 5MM TO RIGHT', fine unmounted o.g. Plate block of nine for comparison. SG 889 var | Estimate - £200-£250 (Image)

1973 Harrison, 1p imperforate colour trial in turquoise, produced for the ''Jumelle Press'' in specially prepared sheetlets of four (this being the bottom left example), full unmounted o.g., very scarce, with turquoise being the issued colour for the ½p. SG X843var | Estimate - £500-£600 (Image)

1973 British Explorers 9p Charles Sturt marginal strip of ten with spectacular spillage of unknown origin affecting seven stamps in varying degrees. Fine unmounted mint and most unusual. SG 927var | Estimate - £200-£250 (Image)

1973 British Paintings 5p 'Sir Henry Raeburn' showing error greenish yellow (skin tones) omitted, unmounted o.g., fine and scarce, offered with normal for comparison. SG 932b | Estimate - £300-£350 (Image)

1979 Rowland Hill Miniature Sheet, showing error Gold (Queens Head) omitted, fine unmounted o.g., offered with normal for comparison. SG MS1099c | Estimate - £200-£250 (Image)

1986 History of the Royal Air Force 22p 'Lord Tedder/ Typhoon'' horizontal pair showing pale turquoise omitted, resulting in the omission of face value and Queen's head respectively, full unmounted o.g., a scarce and striking error! SG 1137a/b | Estimate - £800-£1200 (Image)

1988 £5 'Windsor Castle' deep brown left marginal gutter block of four showing huge 5mm sideways shift of perforations to the left and 1997 £3 'Carrickfergus Castle' reddish violet and gold, right marginal, showing 8mm shift of perforation to the right. Fine unmounted mint. SG 1413 var, 1613a var | Estimate - £150-£200 (Image)

1990 RSPCA 34p duckling, variety 'SILVER (QUEEN'S HEAD AND FACE VALUE) OMITTED', fine unmounted mint with normal for comparison. SG 1481a, £1,000 | Estimate - £350-£400 (Image)

1994-2002 selection of unmounted mint imperforate pairs comprising 1994 Christmas 19p, 1998 Endangered Species 20p, 1999 Settler's Tale 26p, proof, and 2002 Christmas 2nd. Very fine. SG 1843a, 2015 var, 2085 var, 2321b | Estimate - £150-£200 (Image)

1995 Christmas 19p re-issued in 2000 'COLOUR TRIAL SHOWING THE QUEEN'S HEAD AND VALUE IN RED ON A BLANK BACKGROUND', single from the Smilers sheet of twenty (LS2), normal for comparison with Queen's Head and value in silver. Fine unmounted mint. Rare. SG 1896 var | Estimate - £120-£150 (Image)

2001 Double Decker Bus 150th Anniversary 1st se-tenant strip of five, variety 'IMPERFORATE', left-hand stamp vertical crease and slight bends otherwise unmounted mint. Seventeen strips are known of which ten are damaged. SG 2210ab, £3,500 | Estimate - £500-£700 (Image)

2004 Classic Locomotives 47p 'Blackmoor Vale', imperforate left hand marginal block of four, full unmounted o.g., very fine and scarce. Pierron records only 12 mint pairs. SG 2421a | Estimate - £3000-£4000 (Image)

2004 150th Anniversary of the Crimean War 57p, top marginal imperforate vertical pair, showing sheet inscription and pane marker, full unmounted o.g., very scarce, Pierron records only 36 pairs. Photocopy of Brandon Certificate (2006) showing complete sheet of 25 from which this pair was taken. SG 2492a | Estimate - £200-£250 (Image)