Well I know of 2 women who had VBACs in water... one was a HWBA2C... home water birth after 2 caesereans!
I need to add that despite Harman's worries she is quite priviledged to get the opportunity! Very few hospitals do allow it because NICE says you need constant monitoring for a VBAC (which is difficult under water) - yet plenty of research has demonstrated that routine and constant monitoring do raise the chances of management of your labour.
Evidence based midwifery suggests that a problem with a scar (which is the "issue" in a VBAC) can be picked up by other means than a monitor.... a good midwife would be alerted that something wasn't quite right before a monitor would.
Also it needs to be said that the risks of uterine rupture on a woman who wasn't induced is very very low (and it isn't necessarily deadly either!)... you can have a uterine rupture on a normal uterus too by the way!
Specialists in water birth do believe that VBAC women labour better in water as they have more privacy (which helps labour... less privacy = more adrenalin = less release of oxytocyn), they can cope with the pain better.