A problem with claiming on someones insurance if it's their fault 100% is that for some reason, Ive found my own insurance to rise...

Police don't need to be informed or called unless one of the drivers refrains from giving you their details.

Insurance companies I wouldn't have thought would need to be told if you weren't going down the insurance route. Unless im mistaken but I wouldn't see the point (unless you need to document when the accident happened if things went pear shaped?)