Why an historical novel?

I am inspired to write this novel because I live very near Ham Hill, which was the largest hill fort in Ancient Britain, and the Fosse Way. I could therefore provide some geographical authenticy to a story about the Roman invasion of Britain and the reaction of the British tribes who lived there. Ham Hill was built and occupied by the Durotriges who were a particularly interesting tribe, differing socially and culturally from the tribes surrounding them.
Story outline
The Roman invasion is clearly ripe for story telling because it was a time of conflict. Not just between the Britons and the Romans, but between the different tribes, and even within tribes.
The story revolves around Petracus, who is the son of Ham Hill's leader. They have heard from traders that the Romans may have invaded, and Petracus is sent to find out if this is so. He travels east and witnesses the two day battle of Medway, at which the Romans defeat the defending Britons. There he encounters a Hispanic cavalryman Julius, who is disillusioned with his service in the Roman army. Together they return to Ham Hill and report what they have learned. The story goes on to discover how the Durotriges respond to the invasion in the aftermath of Medway, and then when the Romans start to build the Fosse Way through their territory.

Seeking Collaborator
I have researched the Roman invasion and am 25,000 words into the story (60,000 to go). But my knowledge compared with a true expert is negligible I would be delighted to collaborate with an academic or enthusiast with an in-depth expertise on this period in history, in order to assure the greatest possible authenticity.