After amassing various eeze out tools, dremel type drill with varied bits, and flooding old stud bolts with penertrating oil for the past couple of weeks, I set to the task of making my steering lighter.
background these Torx head bolts had been in place 11 years and everyones opinion is that the bolts will cause problems.

Step 1 Car jacked up and drivers Fr wheel off.
Actually Step 1 is obtaining servotronic valve (from Dan, Duckworths for best price) and buying the correct power steering fluid 2 litres (don't think you can find an equivalent on a Saturday afternoon).
Step 2 Have a tray capacity for 2 Litres of oil as when the servotronic valve comes out its a flow not a drip of fluid.
Step 3 Curse the design engineers at BMW for putting the servotronic valve in such a rubbish position and using micky mouse metal stud bolts.
Step 4 Curse them again for using torx head micky mouse metal bolts with no depth to insert the torx bit as they round off on the first take up of strain on the bolts.
Step 5 I then went the route of dremelling a starter hole in the bolt head then inserting an eeze out this turned the bolt which then sheared at the base of the stud as it enters the casting. Bolt 2 I drilled the head off allowing the servotronic valve to be removed (this is when you either catch the oil as it pours out or measure up a blanking plug before starting the job). I was then able to get a small molegrip onto the long stud and work it backwards and forwards once moving it came out easily.
Step 6 back to Bolt 1 with newly purchased flexible drive for dremmel and drilled out the offending broken stud.
At this point I'm up to 7 hours work. No Power Steering Fluid to be had and searching my bolts bin for proper bolts (they have to be the same diameter as originals as there is no clearance along the body of the valve.
Step 7 Take a break put my engineering head back on, pick up proper Power Steering Fluid from LR and search parts bin at work for some aircraft grade bolts.
Step 8 I'll tell how it all went together ....... in due course

Paul

Well all done on Friday and now have speed dependant variable power steering for the first time since I obtained the 04 Vogue a few months ago.
Photo of the offending article with 11years of corrosion on the servo body, no pics of the bolts they were scrap I went to a decent fastener outlet and purchased Cap head bolts spraying them in graphite grease before fit should they ever require removing.
Most useful tools £24.95 Argos Dremmel type tool with flexible shaft and quality drills and Proto tools Eezzi out 5 bit set.
Pig of a job but well worth doing for my shoulders benefit.
Paul