Leak from flat above. who responsible for damage to my flat?

I own a leasehold flat and rent it out. The freehold of the building is owned by a housing association.

The buildings insurance is paid to the housing assoication who cover the whole building.

The flat is let unfurnished, so the tenant contents insurance is covered by the teant. My old insurance company (from when i used to live there) and the housing association both said (verbally) that i would therefore require no additional insurance.

My tenant informed me of sudden leak from the flat above that had leaked into the bathroom of my ground floor flat. I contacted the housing association, who contacted the occupier of the flat above, (who was out at the time) the HA got the water turned off and sent a 'surveyor' round. (It was their property maintenance company). They sorted the damage to the ceiling lighting of my flat and checked the electrics, but my tenant has informed me that there is water damage to the solid oak flooring in the bathroom.

The 'surveyor' told me that this would not be covered by the HA's buildings insurance and that it should be covered the contents insuance policy.

My tenant doesn't want to affect her 'no claims' when the damage was caused through no fault of our own, by the flat above, and it is to the flooring and not 'her' contents. But similarly I don't know it the contents insurance of the flat above would cover it, because the damage is not in the contents of the flat above.

The 'surveyor said: "plumber's findings from the flat above your property, there was a leak from one of the taps (joint) underneath the basin and a small leak from the waste pipe - both in the bathroom"

Incidentally, I understand that there was some major plumbing work done in the above property about a month before, as they had to route pipes down the outside of my property, but i don't know if this was connected.

Could anyone please advise who is resposible for paying for the damage? and what action i should take next?

Many Thanks