Whirlpool Dishwasher ADP 9411 leaking!

Hi all,
Hope you can help out on this one. I have a Whirlpool dishwasher Model: ADP 9411 or (8542 9411 15320) Age: approx 5yrs old
Symptom: After about 2 minutes water appears by running down the front right hand side by the leg.
Checks done to date: 1). Removed underside splash panel held on with 4 Torx 15 screws to gain better visual access. As decribed water started to run down stainless steel wash “drum” but appeared to be between the outer “white” casing and the “drum” 2). Cheched inside the wash “drum” and spotted a white rubber grommet approx 50mm in diameter situated at the right hand upper forward point of the drum. The centre of the grommit is quite perished and has a large hole in the middle. 3). I did a temp job by removing the grommit and replaced it with tape ensuring it was water proof at the edges. 4). Retested and it appears to have stopped leaking.
Do you think I have pin-pointed the solution or can it be something else.? The only other items that I can see may cause the leak are:
1. Drum joint between the lower panel and the right hand side. (appears OK)
2, Upper tray runner mounting rivets right hand side.(appears OK)
3. Faulty door seal (grubby but appears OK )
4. Something else???
Is the grommit a common leak problem for this model.? What causes the rubber grommit to perish? (I have soft water) Also it looks like a whirlpool part number 481246278244 listed on this site.
Regards Brendan