A: Hi
The squealing is probably coming from the bearings in the motor and pump unit, therefore it will need replaced.
The leak is probably coming from the cartridge, which will also need replaced, however you will have to remove the cover to check.
http://www.showerdoc.com/shower-spares/aqualisa/power-showers/AQUAL-PARENT-24-Aqualisa-Aquastream---Thermostatic--Manual(post1997)
Answered 23 days ago | The Doc