The National Institute of Adult Continuing Education (NIACE) took over the work of the Basic Skills Agency more than decade ago. The NIACE site is also now closed, but many of the useful policy and research documents now be found at the L&W Institute. Visit the Downloadable Publications area for dozens of free publications.
For example, I found the 230 page book, More Powerful Literacies (Jim Crowther, Mary Hamilton and Lyn Tett, NIACE, 2014) invaluable when writing the Module 3 essay on language in a social context (New Literacy Studies, literacy as a social practice, etc.) for the Level 4 Certificate in Teaching Adult Literacy in 2006 (since replaced by the Level 5 Additional Diploma). The equally long and interesting Seriously Useless Learning (Alan Tuckett, NIACE, 2014) is another useful source for those studying educational policy and implementation.