Mercedes W211 E320cdi Estate



am having to replace the rear shock absorbers on my E320cdi which has airmatic suspension, I believe the estate cars have different shock absorber to the saloon, I have been trying to locate a source online but can only come up with the saloon shocks, To be clear the suspension has a separate shock absorber to the suspension unit. I was wondering if anyone has done one and if the units are different and what the part number is and what they used to take the head nut off the top which is a circular nut about 4.5cm wide with notches on the edge.

Very many thanks for any help / guidance offered