These are the steps I followed on my Miele Prestige Plus 6 to replace the door seal.
I have no experience or qualifications in washing machine repair - but mine still seems to work without leaking following the procedure. Follow these instructions at your own risk.
Acknowledgement to Mikie_121 (https://www.instructables.com/id/Miele-W1611-Door-Seal-replacement-1/) for giving me enough clues to repair my machine.
Step 1: Turn Off the Power
Unplug the power before you start and wait a few minutes for the capacitors to discharge.
Step 2: Remove the Front Panel Accessory Screws
Unscrew the two screws above/below the door catch and the big screw at the bottom of the door opening.
Step 3: Remove the Outer Rim of the Door Seal
Remove the metal spring which goes round the outside of the rubber door seal (easiest to see where there is a spring at the bottom)
Having removed the metal spring, pull the seal off the lip on the front panel.
Step 4: Open the Drain Plug Flap
Open the drain plug flap at the bottom left of the front panel. You'll need this open to guide the pull ring through when you remove the front panel
Use a small flat screwdriver to open the flap.
Step 5: Remove the Front Panel
Remove the kick-panel. This is not screwed, and is removed with a gentle pull forwards.
Remove the two screws at the base on each side holding the front panel & once removed the front panel lifts forwards and out. Take care to gently unthread the pull-ring from the drain-cover.
Step 6: Remove the Door Catch
Working on the seal is easier with the door catch removed.
The door catch is removed by gently opening the plastic catch holding it in place against the frame.
There is no need to disconnect any leads.
Step 7: Remove the Door-seal
Loosen the retaining ring using the clamp bolt on the left hand side. Once sufficiently loose (but not all the way) this can be removed from the seal.
Remove the rubber hose at the top of the seal and pull the seal off
Step 8: Fit the New Seal
Carefully line the the V in the seal with the two dots on the left hand side of the drum.
Pull the door seal rubber around the rim on the outer drum- this is a bit fiddly - you a looking for a flush fit to the outer-drum around the full circumference. Once the seal is secured re-fit the metal retaining ring and tighten.
The interior of the seal rests against the inner drum, but is not attached to the drum.
Test the inner drum still rotates prior to continuing.
Step 9: Put the Front Panel Back On
Reverse the steps to re-attach the front panel, not forgetting to putt the door catch back first if you removed it.
Take care when replacing the panel to thread the pull-ring back through the slot behind the drain hatch.
Step 10: Attach the Seal to the Door Rim
Pull the door seal over the rim surrounding the door.
Re-attach the metal retaining clamp.