My 16 week old daughter is starting to show signs she will be rolling soon. She currently sleeps in a big bassinet in our bedroom, however is also about to outgrow this and cannot stay in it when she’s rolling. Our room is too small to fit her cot. Her room is right next to ours but with all the SIDS research I’m not sure I’m prepared to move her in there yet. What do we sleep her in, in the interim? Or would her own room in a cot be ok? Thank you. ☺️

Most babies will be rolling by 4 - 5mths - some earlier, some later.
This is very normal as babies grow & become stronger.
Many babies then prefer to sleep on their side or tummy.
This is not something that needs to be stopped. It is important to make their new environment as safe as possible.
https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over

As you have said, it is important, that once baby is making attempts to roll, she needs to be moved to a cot & swaddling/wrapping ceased. Baby needs arms free & the space of a cot to roll well & safely.

Many parents are unable to fit a cot in their bedroom.
Some parents find a portable cot (that meets Mandatory Standards) is helpful to continue room sharing till 6 mths.
If this is not feasible, then a cot (that meets Mandatory Standards) in baby’s own room is OK.
Ensure doors are open & you are able to hear her, & when you wake up during the night, check on her.
No parent is expected to sit up all night watching baby.

Important to maintain all of the rest of the safe sleep recommendations, in particular:
  always place baby on back,
  keep head & face uncovered (nothing loose or soft in the cot)
  provide the safe environment (cot with firm, flat(not elevated) mattress.
Red Nose has the following information

“Parents are not expected to observe their baby constantly. If your baby is sleeping in a separate room check baby regularly to ensure that the baby remains on the back and the head and face remain uncovered (as baby grows beyond 5-6 months they will move around the cot and roll over; settle baby to sleep on their back but let them find the sleep position they feel most comfortable in. A safe cot and safe sleep environment is still necessary for babies older than 5-6 months).”
https://rednose.org.au/article/room-sharing-with-baby