A150 Steering problem?

[idrussell]

After some advice please. Our 2007 A150 seems to have developed a steering fault. After a run especially in the hot weather there is a funny feeling and fizzing noise through the steering wheel. I know the pump is electric, but I presume there is still hydraulic fluid in there? Does anyone know where the reservoir is so that I can check the level. Other than that any suggestions?? The car has done 50k miles and the steering column was replaced 3 years ago just before the 3 year warranty ran out.
Any advice greatly appreciated.
Many Thanks