I need to wash the seat fabric of my doubles kit asap (vomit related). I've removed the seat from the metal frame but I can't find a way to remove the rigid bits inside the seat unit. Is there a way I can remove them so that I can bung it in the washing machine? I really don't fancy handwashing it! Referring to the instructions is no good with P&T as they don't seem to tell you anything about the product and how to operate it