Leak in laundry - Insurance claim

Hello folks,
We have a leak at the laundry trough tap.
The plumber believes the leak comes from the T-piece.
The repair will require removing the tiles at the trough and cutting the plaster board to access the pipework behind. The plumber reckons that the plasterboard might need replacing as it probably will be damaged when removing the tiles. This leads to the whole wall might need repainting to match the repaired areas?
The skirting board has also been damaged and will need to be replaced/repaired.
The skirting board on the other side of the wall has also been damaged (internal wall).
The plumbing repair may be or not covered by the insurance as it may be deemed a maintenance/wear-and-tear issue, although we did not subject the tap ware to any abuse. Probably due to faulty workmanship waiting to fail (house is about 16yrs old).
We are with RACV for home & content and we feel they should cover everything else and we're prepared to pay for the plumbing repairs unless that should be theirs as well.
Trying to get some ammo before launching the claim and any informed suggestion is highly welcome.