Having looked at all three variants this morning if you have tried C00303520 which fits the top two then the only other version left is the bottom one which is part number C00505321.
Don thank you so much for that.
Just need to find an image on Google now.
Nowhere lists that part number.
Qualtex have replied today with that part number as well.
just had exact same problem and just ordered c00505321. this seal seems to be latest machines only, mine was only made in Jan so is not out of warranty yet