Thanks for that Peter. Another supplier website now added to my "bookmarks" Looking at the info on Special, it seems to say that Special and Studional are one and the same but Studional is the more economical buy if you need large quantities.
Thats how I understand it. Rodinal Special does not last any where as long as ordinary Rodinal so I only ever buy it in the small bottles. It was good to meet you on Friday by the way.