Thanks Doc. Still not clear how it works. In Haynes 2004-2008 it says system is electro-hydraulic, ECU is advised by ABS (speed) and a steering angle sensor. Hydraulic pump, reservoir and motor are mounted above the rack and pinion steering.
Haynes 2009-2013, however, states that electric power assisted steering is fitted. It may be the same system, but the description is different, more vague, and does not use the word 'hydraulic'.
I only ask because today my son Ben, with his son Tom (5 last Friday), got into their Astra to leave my house, but came back complainng that his steering 'did not work'. I got in the car and tried it, suspected the power steering, and with engine running tried to turn the steering. Initially the steering was very heavy, but gradually it got lighter and retured to normal. I handed the car back to my son, who drove home in it.
I hope Tom was impressed.
Are the 2006 and 2009 systems identical?