I'm not sure if this card is from the Postcards from Penguin series but it shows the cover illustration from Florence Nightingale, 1959 (series 561 - Adventures from History) by. L. du Garde Peach, illustrated by John Kenney. The book is now out of print. Had I been given a copy of this as a child I suspect it's something I would have enjoyed very much.
The card had another Postcrossing stamp to add to my collection. You can see another stamp in the series here.
{NL-1290603}
Postcrossing card #77