So DS1 has managed to burn a hole in his duvet and duvet cover ...

[Gales]

....probably best not to ask!

I've found some contrasting fabric and am going to patch it and he will have to live with it.

Presumably I need to cut the burnt fabric out, which will leave me with a hole about 6cm across. Do I need to hem that before stitching the patch over it?

oh I have to ask

HOW??

I'm wondering how old Ds1 is

I think just hem the patch and stitch it on. I'm not a sewer though I'm just trying to be vaguely helpful in the hope you will give us more info about what happened

Was it by having a light under the covers and light bulb burned it?

YES do hem first all around the frayed edges, Best if you could fold them back and stitch the hem inside, iyswim.

Same with piece to patch with, fold edges back in.

Not smoking then?

I think it was an exciting chemistry experiment!

Thank you! Nothing exciting, a lamp had been left on the bed. Makes me shudder to think what might have happened if he'd left the room

get an additional smoke alarm too.