Leaky Stem Adapter - thread issue ?

[Le Rouret]

Hello.
Installing a shiny new Hudson Reed shower in France...
The shower comes with two stem adapters.
No matter how hard I tighten these they leak significantly....
BUT if I then remove shower and screw in the previous end caps...no leaks..in fact I only need to hand tighten these..
Pictures attached...could this be a thread issue ??
Thanks in advance.

 

[ShaunCorbs]

They leak from the threaded in the wall connection or the one onto the shower valve ?

 

[Le Rouret]

They leak from the threaded in the wall connection or the one onto the shower valve ?

Hi...sorry not clear....wall connection...shower valve is sound.

 

[ShaunCorbs]

Need more ptfe min should be around 15 wraps

 

[Le Rouret]

Need more ptfe min should be around 15 wraps

Thanks...did the job...tape I have here seem incredibly thin...had five turns but twenty seems about right after some trial and error..