Patricia Leitch wrote four pony books under the name Jane Eliot. These were first issused as Collins Spitfire paperbacks: these are notable for being a lot smaller than the normal paperback format - a tiny 5.5 x 3.5 inches.
The first three titles were re-issued under the Collins Pony Library imprint, under the name Patricia Leitch, and with the stories expanded.
Afraid to Ride
Collins Spitfire, pb, 1967
First Pony
Collins Spitfire, pb, 1967
Jacky Jumps to the Top
Collins Spitfire, pb, 1967
Pony Club Camp
Collins Spitfire, pb, 1967