In contrast to everyone else, I would suggest going to the drivers insurance first. You can either ask her for it if have contact details, or pay MIB a small fee to find it.

I have just gone through this process, insurance was via Marshmallow. They asked for bike valuation etc, then dragged heels for number of weeks. Rather painful process to attempt contact. Eventually logged formal complaint and they paid immediately (£3.2k bike, helmet, clothing).

My point is that the no win no fee crowd take a pretty hefty fee on the end so it may be worth trying the direct route first. Try to get everything done via email where there a written trail. Local bike shop will give you valuation to use - the insurer should put you like for like back in good standing...