I had 2 c-sections and wanted a v-bac for my third. I saw a lovely consultant midwife who was really supportive, the risk of scar rupture is really very very small. See if your hospital or area has someone like this? She covered a few hospitals in South Wales, not just mine.
Unfortunately in the end, I had my third c-section at 15 days overdue - by that stage I really didn't care how the baby got out!
Good luck with it all, I was surprised by the relaxed attitude of all the medical people I saw, I think it's becoming a lot more common now so they don't feel like we're asking for something unusual/risky.