Oh good grief, hire an independant midwife and have a homebirth is my advice. They're much more likely to be happy with no routine VEs.
See this page for other ways they can tell your progress.
I agree with you, that if you've laboured at home and got to the stage where you want proper support/pain relief, then you are definitely in labour! It may stall and all die down again, but that could happen at almost any dilation!
Some women get the urge to push before they are fully dilated - and the pushing actually helps dilate further. Other women are told not to push before 10cm and tire themselves out with desperately trying not to push. Others get to 10cm and are told to push - they tire themselves out pushing for hours without the urge, by the time the urge comes they have hit the wall and need assistance.
Read this page about pushing for first time mums, it says some sensible stuff.
Keep reminding yourself, the midwives cannot tell you that there is no other option - they have to have your permission, you have the right to refuse.
In hospital, if you were wondering about a labouring in water for pain relief, they would probably not like you to get in before 6cm, so would want to do a VE for that. If you were at home, however, you could get in whenever you wanted to (bearing in mind that getting in too early can stall labour of course).
What I don't know is - are they within their rights to withhold gas&air etc if they decide they can't tell without a VE whether you're in labour or not??