I have been to Waterstones and I have found some Shoe books that have helped me in my ideas:
A celebration of pumps, sandals, slippers & more- Shoes- Linda O'Keeffe

Shoe Fleur- A footware fantasy- Michel Tcherevekoff

Custom Kicks- Maki

Stepping Out- Three Centuries of Shoes- Powerhouse Publishing

Shoes- Lucy Pratt and Linda Woolley- V&A