Legal standpoint ?

Get estimates for any repairs and bills for any work done so far and send her the bill with a timeframe before you will issue court procedings to recover the costs.

Search LBA or LBC etc.

She will have the choice then of paying you directly or getting her insurance to pay. If she is insured for renting the property.

Cracks though maybe just property movement and fairly normal.

Legally you have no right to claim against her insurance policy - it's there to protect her, not to protect you. Home insurance is not like car insurance where you have a right to the other party's insurance details after an incident - in fact there's no legal obligation on her to have insurance at all (though if she has a mortgage doubtless the mortgage company will insist on it).

What you can do is attempt to claim against her personally, and if she doesn't fancy defending or paying the claim herself she can pass it onto her insurers to deal with on her behalf. The insurers will only pay if they judge (or a court finds) that she is legally liable for the damage. The fact that the leak came from her property does not in itself make her liable - she is only legally liable if the damage was the result of negligence on her part. Negligence means a failure to take the level of care that would be expected of a reasonable person - if you can't prove that then your options are to pay for the repairs yourself or to claim on your own insurance.

Alternatively you could claim on your own policy, and if your insurer thinks there's a realistic chance of claiming the costs back from her they will do so on your behalf. Don't get hung up on the "but I shouldn't have to claim if it wasn't my fault" way of thinking - most claims that you might make on your home insurance policy (floods, storms, fire, burglary etc) are for things that are not your fault. Plus your insurer may well require you to declare the damage whether or not you make a claim