Hello We purchased an Uppababy with a portable cot. We were told that due to the flap at the bottom which allows airflow that it is safe to use use as a porta cot for overnight sleep overs. I am getting mixed msg online and don’t want to use in fear of the possibilities. Are you able to help? Cheers Abby

Red Nose recommends only using a portacot that meets mandatory Australian standards. (AS/NZS - 2195)
https://rednose.org.au/article/portable-cots
https://www.productsafety.gov.au/products/babies-kids/kids-furniture/folding-cots

Are you referring to the use of the pram or as a bassinet?
..........Yes

There are no Mandatory Standards for bassinets in Australia.
Product Safety (ACCC) Australia develop & monitor safety standards for products.
They provide the following information (as Buying Tips) to look about bassinets.
However, these are not mandatory, they are safety recommendations.
I suggest you look at the full information on the web site, & if possible.
Any concern about unsupervised sleeping in a pram is particularly related to the height of the sides.

Ensure the sides of the bassinette are at least 300 mm higher than the top of the mattress base.
Ensure it has a wide stable base and a sturdy bottom so that it won’t tip over.
Ensure the mattress fits well and is firm, smooth and no more than 75 mm thick.
If the product has folding legs, make sure it cannot accidentally fold during use.
https://www.productsafety.gov.au/products/babies-kids/kids-furniture/bassinettes

Product Safety also has the following information for Prams.

Avoid sleeping children in prams or strollers.
Never have an unharnessed child asleep in a pram or stroller as they can move about and may be at risk of falling or entrapment.
If they are asleep, maintain regular supervision.
https://www.productsafety.gov.au/products/babies-kids/kids-equipment/prams-strollers

Red Nose also provides information for bassinets & prams.
https://rednose.org.au/article/bassinettes

Never leave your baby unattended in a pram or stroller. It is not a substitute for a cot.
https://rednose.org.au/article/prams-and-strollers

As far as the “approved for overnight sleeping” is concerned, this is a USA, not Australian standard.