X-Type 2.2d light steering issue??

[cartart]

Wisdom required please:

53k on clock and the steering seems to be getting lighter and more twitchy by the week. Has been checked twice for wear in joints etc. New brake pads and tyres recently (3 months) On the motorway I can feel every breath of any side wind/breeze and on fast bends on dual carriageways etc I have to "settle" the car into the curve, any twitch on the steering wheel and things feel a bit unstable and scary. I did check and top up the power steering fluid which was off the little dipstick and tyre preassures also checked and pumped to 38 PSI as recommended by Jag mechanic (?)

Any advice on what might be worn/need replacing?

Thanks