University College London
Special Collections at UCL is one of the leading university collections of manuscripts, archives and rare books in the UK. Its website is detailed and includes a searchable catalogue of its manuscript collections. See http://www.ucl.ac.uk/library/special-coll/
The Schreiner/Schreiner Related Collection held by UCL Special Collections is:
Karl Pearson: The Pearson Collection is a very large one, composed by Pearson’s manuscripts and papers relating to his polymath activities as a writer, mathematician and eugenicist and a busy university academic and journal editor. As well as many letters to Pearson, it also includes the papers of the Men and Women’s Club of which he was the founder. Schreiner’s letters to Pearson, Elisabeth Cobb, Maria Sharpe and Robert Parker are part of this sub-set of material. There is a useful finding aid.