There is a paper by E. C. Cawte in the current edition of The Folk Music Journal (EFDSS, London, 2003) which you would certainly find interesting: Watching Cecil Sharp at Work: A Study of his Records of Sword Dances Using his Field Notebooks.

The material at the Vaughan Williams Memorial Library is very specialised. There is an ongoing project to make at least some of the catalogues and photographic archives available online, but you have to understand that this is a small, private library, and that it is not funded by the state. Money and resources are very scarce. If you want them to make their holdings available online, you should consider donating money to help them do it.

They also need, very badly, financial help to safeguard the physical integrity of the manuscript collections. They do an extremely good job in far from ideal circumstances; in almost any other country in the "civilised" world, government would be providing proper funding for such a valuable collection of traditional culture. Unfortunately, government in the UK appears to believe that musical "culture" begins and ends with Opera.