Fantastic trail route.
Firstly you need to do some research because there are very few Brit Valley Way signs.
Be careful because this is not the Brit Valley Circular walk - that's for another day.
I did Chedlington to West Bay because my in-laws live there. Its clearly quicker this way BUT you get utmost respect for doing it other way around. My fkt includes close to 5 miles of errors so you could easily check out Strava - chop out the switch backs and go quicker!
Route is overgrown in parts - plenty of waist high stinging nettles if you love em.
With so many runners sticking to the Dorset coastline (because it is so gnarly and beautiful) you owe it to yourself to see how beautiful it also is inland.
This route is crying out for a Race Director to turn it into an out-n-back. I will definitely do this when I'm back next month.
Enjoy.