if she hit you in the side whilst you were on the roundabout then she has clearly not given way to you.

if you present the facts as they are then she does not have a leg to stand on and the fact she left the scene of the accident is also another big mark against her...

What are the police saying about it ? If they attended the scene then they will have a report on what happened based on witness reports and the physical scene.

it's probably standard policy for the ins co to start from 50-50 but once the facts are laid clear it should be a no brainer, she was at fault...

good luck..