The history of economic thought is a wide intellectual domain that stretches across time and space and overlaps with other disciplines. Here follow some links to other sites and communities that relate to the history of economic thought.
For information to archival collections that contain papers from or about British and Irish economists through the ages the best place to start is EconomistsPapers. This website is sponsored by the Royal Economic Society and is building on a work by Paul Sturges Economists’ Papers 1750-1950; A Guide to Archive and other Manuscript Sources for the History of British and Irish Economic Thought (1975).
Even though that list is quite long, this does not mean it is comprehensive. If you cannot find information about the British author you are interested in your next best step is to search through the catalogue of the National Archives (which also will return results for many other archives in the UK).
In recent decades history of economic thought has not been taught as widely at UK universities as it was in the past. There is however something of a revival in the last few years, with new courses being offered. One good website for materials and course outlines is run by the History of Political Economy Centre at Duke University.
Other HET Societies
There are a number of international societies of historians of economic. The largest ones are the European Society for the History of Economic Thought (ESHET) and the North American History of Economics society (HES). Recently a South American society (ALAPHE) was founded. Then there are many national societies, like those of Australia, France, Italy, and Japan.