I found this website when looking up some more infromation on Food rationing in War Time Britan, http://www.history.ac.uk/research-training/browse/online which is a course offering from the Intutute of Historical Research University of London School of Advanced Study. It is a sourse that helps set up a research data base to keep track of the data that you are acumulating. Looks like a Good program to go through to help researching skills.
http://en.wikipedia.org/wiki/Rationing_in_the_United_Kingdom#CITEREFHome_Front_Handbook an Entry on the Wikipedia for rationing in the UK, there are some resources there worth looking into for furthur investgation.
http://www.bbc.co.uk/blogs/food/2011/01/how-to-make-marmalade.shtml A BBC blog entry on Marmalade with happened to be one of the items availble during the war for a ration item.