Mattress protector?

[sorryiasked]

I need a protector to fit a thin single mattress. I can't find anything to fit less than one 11" thick.
It doesn't need to be waterproof or quilted, but can be.
However it needs to zip close, not have elastic straps or fitted sheet type elastic.
(It's to go on a high level cabin bed, we have a fitted sheet one at the mo and it's a nightmare, forever slipping)
Any recommendations gratefully received.
I think I may end up getting a topper to go inside the protector but even so it will be less than 11" thick.

Hopeful bump

Not exactly to brief but these are top sheets with integrated mattress protector, which would eliminate the need for a separate mattress protector at all. https://shop.eric.org.uk/products/hippychick-fitted-sheet-mattress-protector

A waterproof mattress would be the other option, but they are expensive.

@sorryiasked you need to look at incontinence sites like ERIC as posted above, there are lots of people who need this sort of bedding, you just have to know where to look. If you google zipped waterproof mattress topper <insert depth in cm> there are lots to choose from you just need to find one for your mattress depth.

Thank you, I'll try more searching but couldn't come up with anything less than 11" thick.

A company called Jonic may be able to help. https://jonic-uk.co.uk/