Powerless Aqua Lisa power shower?

I have a power shower that is rapidly losing more and more power. It's located in a loft conversion, and has been fully operational for 2 years. The bath,which the shower is located over, and the sink are both fine.
The silver casing has been pulled at(thanks to my kids!!) and is starting to unravel a bit, but there does not appear to be any leakage.
Would be greatful for any help.Thanks