Dominique Gonnet from the Sources Chretiennes has drawn my attention to a little known Greek Orthodox site, http://www.anastasis.org.uk/. It is the property of an “Archmandrite Ephrem” and it contains English translations of all sorts of snippets. In particular there are a number of letters and sermons by Ephrem the Syrian, translated here. I think few of these exist in English otherwise.
There are no contact details on the site, and the last date I could find was 2008.