I was told by a midwife that by the time they are rolling you don't have to worry about trying to back sleep them.

She said the main thing when they tummy sleep is to not over dress them or have too warm blankets/ too heavy sleeping bag on them because the SIDS risk with tummy sleeping is mostly from overheating. Apparently they are less likely to overheat on their backs (so she told me).

I was a tummy sleeper from birth and it didn't do me any harm, so was my DF.

My son is already starting to do the same thing (or an his side) as the back sleeper can't contain him anymore & he manages to roll perfectly well in his sleeping bag.