I used the top sheet to wrap my babies once they got a bit bigger (since none of the wraps are big enough for babies over 4 weeks old).

You can use top sheets and tuck your baby in firmly. Some babies love being tucked in tightly (my DS did even while he was wrapped) and some hate it (both my DDs did). You are just meant to make up the bed with the babies feet touching the bottom of the cot and the sheet is not meant to pull up any higher than their neck.

We followed the SIDS guidelines pretty stringently and put nothing else in the cot with them. It really annoys me that shops are still allowed to sell things like cot bumpers that go against SIDS recommendations. Car seats, high chairs, everything else you buy for a baby (including the cot itself) have to meet a safety standard but the SIDS ones are negotiable. I don't get that.