Hi, What materials do you recommend for mattress protectors? We are moving our 5 month old into her cot which is odd-sized, so we need to have bedding custom made to ensure a tight fit. Is Terry- towelling plus PVC okay or should we avoid plastics for breathability? Thanks

Does the cot meet mandatory Australian standards?
Red Nose recommends that a mattress is firm, clean, well-fitting & flat.
If you are also getting the mattress custom made, ensure there are no gaps greater than 20mm between the mattress & the side, where baby may be at risk of entrapment.
A mattress protector should be strong & a tight fit - not padded, which may reduce the firmness of the mattress. Never put soft bedding under the sheet.
https://rednose.org.au/article/what-is-a-safe-mattress
Red Nose does not recommend any specific type of material for a mattress protector.