anchor.diff:  WESTERHAM,1959
   WINCHESTER,1962
   WINCANTON,1963
  +HORNSEA,19642
  +HORNSEA,19645
  +HORNSEA,19648
  +HORNSEA,19649
  +PATRINGTON,19643
  +PATRINGTON,19644
  +PATRINGTON,19646
  +PATRINGTON,19647
   STRONTIAN,1967
   PENICUIK,1968
   LEYBURN,1969
  
positive.code: CHURCH STRETTON,1694
  SKELMERSDALE,1695
  BRAMPTON,1697
  MOTHERWELL,1698
  ROTHESAY,1700
  SOUTHEND-ON-SEA,1702
  
negative.code: LOOE,1503
  JOHNSTONE,1505
  BATHGATE,1506
  ALFORD (LINCS),15074
  ALFORD (LINCS),15078
  ALFORD (LINCS),15079
  LOUTH,15073
  LOUTH,15076
  LOUTH,15077
  SPILSBY,15072
  SPILSBY,15075
  BROOKE,1508
  LOUGHBOROUGH,1509
  LIVERPOOL,151
  LOCHCARRON,1520
  LINCOLN,1522
  LANCASTER,1524
  HORNBY,15242
  LEIGHTON BUZZARD,1525
  MARTIN,1526
  REDDITCH,1527
  