My 5 month old keeps moving around the cot and subsequently rolling over and bumping head. I don't want to purchase cot bumpers because of the risk but found this sleepwrap instead. https://www.safetsleep.com/collections/sleepwrap-baby-wraps/products/sleepwrap-baby-wrap-classic?variant=739083269 Is this safe to use?

Most babies will be rolling over by 4- 6 months. This is very normal as babies grow & become stronger.
Many babies then prefer to sleep on their tummy.
This is not something that needs to be stopped. It is important to make the new environment as safe as possible.

Also ensure that the mattress is firm & flat & there is nothing soft or loose in the cot.

Always place baby on back to sleep.
Increasing tummy time when awake is also helpful.
If you are still wrapping your baby, this need to be ceased - babies needs arms free to move & roll safely.

Red Nose has the following information now that your baby is starting to roll.

Give baby extra tummy time to play when awake and supervised as this helps baby to develop stronger neck and upper body muscles which in turn enables them to roll back over.
Make sure that baby is on a firm and well-fitting mattress that is flat (not tilted or elevated).
Make sure that baby’s face and head remains uncovered (do not use lambswool, doonas, pillows, cot bumpers or soft toys)

As babies grow and develop they become very active and learn to roll around the cot.
At this time, continue to put them on the back at the start of sleep time, but let them find their own position of comfort.
By this stage it is not necessary to wake during the night to turn baby over to the back position

Red Nose does not recommend the use of any devices that attempt to prevent a baby rolling.
Rolling is a normal stage of development & once baby is rolling, it is important to make the sleep environment as safe as possible.
Always place baby on their back to sleep.
Do not use any devices designed to keep baby in a particular sleep position.
https://rednose.org.au/article/what-do-we-do-now-that-a-baby-has-started-to-roll-over