Rather than use a solenoid of sorts to turn a valve body where you get into torque and rotational stops I believe what you want is a solenoid valve for water. Valves of this type can be expensive. However, an inexpensive choice would be to remove them from old washing machines. The problem then becomes that solenoid valves used in washing machines will run of the mains voltage in the country they were designed for. Based on your link I assume you are in the UK.
Most valves of this type I have worked with have a brass or stainless steel valve body and are expensive (depending on what you call expensive). You may be able to find some inexpensive plastic body types that use a DC coil. There are also latching types where current isn't applied to the coil constantly. Valves like this come in all flavors and designs. Normally Open or Normally Closed, shuttle types, and the list goes on. Anyway, depending on the volume and pressures involved you might do well looking for inexpensive, plastic body water type solenoid valves.
Ron