My 16 week old is rolling has been rolling from her back to tummy for a while but has only in the last week started to roll from her back to tummy. I am moving her into her cot and using a sleeping bag with arms out. I was advised on a safe T sleep wrap as she is rolling onto her stomach in her sleep. Are the safe T sleep wraps safe to use?

Moving baby into her cot and having her arms free is exactly what Red Nose recommends now that she is rolling.
We would encourage you to also increase her supervised tummy time to further help develop her muscles and aid her in rolling both ways confidently.
Red Nose does not advise the use of any devices that restrict baby from rolling onto her tummy.
At this age it is quite common for babies to be rolling and a very natural and normal developmental milestone.  For further information about baby rolling please see our information statement: https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over