Kate's Closet - I've been in contact with Gianvito Rossi and they have confirmed that Kate wears their Gianvito 105 suede pumps in 'Praline'. This is the official name of the colour.
Kate Middleton's Gianvito Rossi Mila d'Orsay Sandals in Black Suede
Kate Middleton's Gianvito Rossi 105 Pumps in Praline Suede
Pumps GIANVITO 105 | Gianvito Rossi
The Royals Accessories: GIANVITO ROSSI Gianvito 105 Praline Suede Pumps
Pumps GIANVITO 105 | Gianvito Rossi
Pumps GIANVITO 105 | Gianvito Rossi
Kate Middleton's Gianvito Rossi 105 Pumps in Praline Suede