Several examples of 3 consecutive winters. A whole base had an asdditional extra year - Stonington winter 1949 - among the fids was Bernard Stonehouse. You are correct with the 2 Halley Fids in the 60's - also I believe Jim Shirtcliffe did 3 consecutive ones in the 60's. Also Paul Gurling did 3 in the late 60's early 70s. BAS don't encourage it - it takes even longer to re acclimatize to "civilisation" when you get back. I think most number of winters is still held by Kenn Back at 10 or 11.