Are you focusing only on UK education here? Are you looking at this from a policy perspective or is it the teaching methods you are focusing on?
You may want to go down the line of topics such as educational change, history of education, curriculum development and so on? I did a few searches in the education indexes and on the IOE library catalogue to see what was available. There is a great deal of literature about the national numeracy strategy, which is not surprising, however, not as much as I expected about the history of primary numeracy teaching. So, ultimately you may need to broaden the search a bit more.
The book below look like it could be useful? Also, a rather dated article from Mathematics in School journal and some evaluative conference papers and articles from Dylan Jones.
I hope this helps.
Teaching and Learning Primary Numeracy: Policy, Practice and Effectiveness
Institute of Education library catalogue
Brown, M. (1999). 'Swings of the pendulum: a history of primary numeracy'. Teaching and Learning Number in the Later Years of Primary School (ed. I. Thompson). Buckingham: Open University Press
British Education Index
NOTE: For information about accessing full text articles please read this TTRB article: Access to full text journal articles
The history of mathematics in the primary school. Mathematics in School, March 1994, vol. 23, no. 2, p. 34-35, ISSN: 0305-7259. Gardner-J-Helen.
Learning from recent numeracy initiatives in England and Wales.
Paper presented at the British Educational Research Association Annual Conference, Heriot-Watt University, Edinburgh, 11-13 September 2003. The text is in the Education-line internet document collection at: <http://www.leeds.ac.uk/educol/documents/00003855.htm>, 2003, pp. 23.
A comparative analysis of national numeracy initiatives in England and Wales.
Paper presented at the British Educational Research Association Annual Conference, University of Exeter, 11-14 September 2002. The text is in the Education-line internet document collection at: <http://www.leeds.ac.uk/educol/documents/00003854.htm>, 2002, pp. 14.
National numeracy initiatives in England and Wales: a comparative study of policy.
Curriculum Journal, Spring 2002, vol. 13, no. 1, p. 5-23, ISSN: 0958-5176.
The National Numeracy Strategy: are we getting it right?
Psychology of Education Review, September 1999, vol. 23, no. 2, p. 3-21, ISSN: 0262-4088.