That SWF is the first record for your tetrad! In other news: a Wall with the ground colour white instead of orange was photographed yesterday at Salthouse - this is ab. xanthos; second brood swallowtail now flying; Ladybelt Park has several Clouded Yellow flying, suggesting they bred there; and Chalkhill at Warham Camp now 500+ and still rising.
Very - but it might have been sleeping for a few weeks and been disturbed. They tend to go into hibernation quite quickly so they often look pretty fresh even in March - it's flying around that gets them tatty rather than age per se.