Help fitting a concealed shower head please

[Aj1]

Hey!

I am trying to finish off fitting this shower head but unfortunately seem to have run into issues accessing the thread. I’ve attached a couple photos of the issue. Would anyone know what would be required here? There’s tile then plasterboard, a cavity then where i have good access theres another board between it. Also, the chrome plate that goes on the end of the shower head won’t go past the end of the thread but that’s understandable.

Would i need some sort of thread extension or is there any methods you’d suggest? Thanks in advance!

 

[Bonni]

Get an old bathroom sink tap and cut the tread off. There's your extended thread. Then get a suitable fitting to join it onto the concealed shower fitting.

Why? My plumbers merchant gave me that advice and it worked, and I've been in the game for over 19 years and just found that trick out!