Smeg DI612CA Dishwasher – water feed tube plastic bearing

I want to know the name of the part I need to order, inside the dishwasher, it is the bit on the inside back panel of the dishwasher that the spray arm feed pipe slots into, the part comes through the back of the dishwasher and then has a kind of plastic bearing on it that looks like a flower shape which has broken off.

Should I call an engineer out for this or can I repair this myself, if I can do it myself does anyone know what part I should be looking for or part number?

I would be really grateful for any advice

Thanks Marilyn