There are two numbers before each butterfly species, the first is known as the "2013 checklist number" and the second number, prefixed with "BF" is the original "Bradley and Fletcher number", however this BF number looks as if it will be phased out in time.
57.001 BF1532 Dingy Skipper, Erynnis tages
57.002 BF1534 Grizzled Skipper, Pyrgus malvae
57.005 BF1527 Essex Skipper, Thymelicus lineola
57.006 BF1526 Small Skipper, Thymelicus sylvestris
57.007 BF1528 Lulworth Skipper, Thymelicus acteon
57.009 BF1531 Large Skipper, Ochlodes sylvanus
58.003 BF1553 Orange-tip, Anthocharis cardamines
58.006 BF1549 Large White, Pieris brassicae
58.007 BF1550 Small White, Pieris rapae
58.008 BF1551 Green-veined White, Pieris napi
58.010 BF1545 Clouded Yellow, Colias croceus
58.013 BF1546 Brimstone, Gonepteryx rhamni
59.002 BF1615 Wall, Lasiommata megera
59.003 BF1614 Speckled Wood, Pararge aegeria
59.005 BF1627 Small Heath, Coenonympha pamphilus
59.009 BF1629 Ringlet, Aphantopus hyperantus
59.010 BF1626 Meadow Brown, Maniola jurtina
59.011 BF1625 Gatekeeper, Pyronia tithonus
59.012 BF1620 Marbled White, Melanargia galathea
59.013 BF1621 Grayling, Hipparchia semele
59.017 BF1608 Silver-washed Fritillary, Argynnis paphia (And valezina -type)
59.019 BF1607 Dark Green Fritillary, Argynnis aglaja
59.021 BF1584 White Admiral, Limenitis camilla
59.022 BF1585 Purple Emperor, Apatura iris
59.023 BF1590 Red Admiral, Vanessa atalanta
59.024 BF1591 Painted Lady, Vanessa cardui
59.026 BF1597 Peacock, Aglais io
59.027 BF1593 Small Tortoiseshell, Aglais urticae
59.031 BF1598 Comma, Polygonia c-album
59.033 BF1610 Marsh Fritillary, Euphydryas aurinia
60.001 BF1582 Duke of Burgundy, Hamearis lucina
61.001 BF1561 Small Copper, Lycaena phlaeas
61.003 BF1556 Brown Hairstreak, Thecla betulae
61.004 BF1557 Purple Hairstreak, Favonius quercus
61.005 BF1555 Green Hairstreak, Callophrys rubi
61.006 BF1558 White-letter Hairstreak, Satyrium w-album
61.010 BF1569 Small Blue, Cupido minimus
61.012 BF1580 Holly Blue, Celastrina argiolus
61.014 BF1571 Silver-studded Blue, Plebejus argus
61.015 BF1572 Brown Argus, Aricia agestis
61.018 BF1574 Common Blue, Polyommatus icarus
61.019 BF1576 Adonis Blue, Polyommatus bellargus
61.020 BF1575 Chalk Hill Blue, Polyommatus coridon