Fiamma Waste Water Tank Cap Replacement

Anyone know where to get a replacement white cap for the Fiamma 23L Roll away waste water tank?

Tried to upload picture of the fiamma tank, but no joy!

Hi Dago

Fiamma list the caps on their parts page here but I see no option to purchase 
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I would phone Fiamma and ask them. We have done this with two different companies recently after losing a cap on a vacuum bag, and having a spring go on a flip top waste bin, and received excellent service from both companies. Certainly worth a try - it's always our first move. Good luck!