Elisabeth Grant did frontispieces for the last hardback edition of the Jill books.  These had laminated boards with photographic covers.  I have only seen one of these editions, which had no internal illustrations, and just the frontis by Elisabeth Grant.  This is one of the hardest editions to find, so I haven’t been able to check if any edition has extra illustrations by her.

Elisabeth Grant illustrated other pony book authors as well:  some of Gillian Baxter’s were done by her.  I do like the Jill ones.  She manages to make Jill look the right age and like a proper girl (even though Black Boy is, sadly, a piebald).  I wonder if Elisabeth Grant was the uncredited artist responsible for some of the Armada covers:  to me there seems a similarity in the style.

The illustration to the right is from Jill Enjoys Her Ponies.