Leaking Tap under bath

[Micky]

Hello, I have just fitted a victorian bath tap with shower attachment, 2nd hand. It is fine until I turn it to shower and cold water is leaking from where the tap is attached to the underside of the bath. The water coming out is cold so I am asuming that it is something withing the cold tap mechanics. I am hoping to get a look inside the taps this weekend to work out the problem but would welcome any advice!

 

[Bas]

is the water dripping onto the bath and leaking through the hole in the bath?

 

[Micky]

There does not appear to be any water coming over the top surface of the bath.
Where the large screw pipe (for the tap) comes through the hole in the bath it is secured with a black plastic nut. The water is squeezing its way between the underside of the bath and the plastic nut. Definately cold.

 

[Bas]

if it only happens when switched to the shower and is definitley not a leaking connection between the tap and copper supply pipe then the tap must be faulty

 

[Micky]

And not repairable?? maybe will have to look at replacement! Thanks for your help.