leak and liability

Hi,

I appreciate that there are a couple of examples on here already of those who have had leaks from neighbours but i'm not clear on how this effects my particular situation.

I own the share of freehold of my ground floor flat, the flat upstairs is currently let out by its owner and their boiler valve has leaked and caused a flood in my kitchen. The ceiling now has holes in it to let the water through.

Once the ceiling has dried is the owner of the flat above responsible for repairing my ceiling? How do i go about making a claim as such? Also can i insist on him having a registered plumber to come in and repair his boiler?

Thank you for any advice you can offer