How do I help my downstairs neighbour with a leak without agreeing to a bill before the cause is known?

My downstairs neighbour held up a photo of a wet ceiling patch and said, “It's under your bathroom. Can you pay the £160 plumber callout?”

We rent separate flats in England, with different landlords. I went upstairs and found the floor dry, the bath empty and no obvious drip. That doesn't prove nothing is leaking. It only means I couldn't see the source.

I sent the photo to my landlord and reported the problem straight away. My neighbour sent it to hers. Her landlord offered an inspection tomorrow; mine has asked when someone can look in my bathroom. I can be home after four, but she wants somebody sooner because she has moved her desk out from under the patch.

The [GOV.UK repair guidance](https://www.gov.uk/private-renting/repairs) says landlords are responsible for plumbing repairs, while tenants can be responsible for damage they cause. We do not yet know what has happened here. I don't want “it's below your bathroom” to become my agreement that I caused it.

I offered access and suggested copying both landlords into one message. She heard that as passing the problem around: “I'm the one with water on my ceiling.”

How can I make clear that I am helping to get it investigated urgently without promising to pay an unagreed bill? I can see why she wants a decision today; I don't know which decision is mine to make.