Apologies for my poor etiquette, I have not used a forum before. Eventually I managed to solve the problem, I had already done what you had suggested Jeff, thanks though, and it seemed not to be working. However I just needed to bring my possible markers closer. Due to the length of the film, there was a very small window, about a minute and a half that was eligible for a dual layer break, so i peppered part of the timeline with 100 markers one every 25 seconds and eventually about four showed up. So in the end all the advice I had read was correct I just didn’t think it was working because I put the markers too far apart. There are definitely still strange things in DVD studio pro, like the fact you can set the dual layer point in two separate places and they don’t seem to align. Also, there is some inconsistency in which markers are allowed, I could only get ones recognized in the advanced burn/format tab, anywhere else and it just wouldn’t let me. Anyway, thanks for the help.
Jack