Hi. My baby just turned 7 weeks and I've just put him in love to dream swaddles. I place him on his back and then he rolls to the side (during light sleep I think). He was doing it when we tried the Love to Dream swaddles at 1.5 weeks old too. I am petrified to fall asleep incase he rolls into his stomach. I thought babies don't roll until they are at least 4 months old?

Most babies don’t start to roll intentionally till about 4 months - some not until 6 months.
Red Nose recommends always place baby on back to sleep.
However, there seems to be a number of babies who roll to their side at a very early age, as you are describing.
Sometimes it is because these babies do not respond well to wrapping, & are less likely to roll when unwrapped, (ie both arms out)
It may also be helpful to wrap under arms only, using a muslin wrap.

See information & graphics under principles of Wrapping here: https://rednose.org.au/article/wrapping-babies
Modify the wrap to meet the baby’s developmental changes, e.g. arms free once ‘startle’ reflex begins to disappear which is usually around 3 months;

Ensure cot mattress is firm, well-fitting & flat.
Ensure there is nothing loose or soft in the cot.
Preferable to use a sleeping bag now that has appropriate size neck & arm holes.
Increase tummy time when awake to continue to strength upper body.

Red Nose does not recommend positional products such as anti-roll devices and items that fasten a baby into a sleeping position.
Products that restrict the movement of a baby or a baby’s head should not be used.
This is because there are no Australian Standards for these products and case studies have shown that these products can be unsafe.
https://rednose.org.au/article/is-it-safe-to-use-products-designed-to-keep-baby-in-a-particular-position