Water coming out back of shower how can i fix it?

I have a gainsborough shower and when you push the start button water flows out the back of it.
When i stripped the front panel off to what is going on and removed the plastic connector that you screw the shower head to there is a ball with some w/proof putty bunged in the end.
I have stripped it down twice retightened all screws but to no avail
Help.
Could it be that when i turned on the water from the rising main , I put too much pressure to the system and blew the shower as it says max inlet pressure 10 bar?

Phil Stokes
March 2012