Minor point,but worth checking if your estate groans when rear door is opened;

My 1.9TDI Classic Estate (Jan'07) groaned whenever I opened the back door - for several months.

Tried oiling the moving bits,except the shiny bits on the struts.

Above did not help.

Then finally discover yesterday that the peg that is screwed into the car body on the driver's side was loose,because the peg was under load when the door was open, did not appear loose.

Groan or creak was caused by the bottom plastic bit of the strut rubbing on the car body when rear door being opened/closed!!

Peg tightened up & now like new!