Thanks everyone.
The garment in question is a top for my daughter made of a lightish weight viscose jersey with quite a bit of stretch. Most of it is loose fitting but the problem area is round the armholes as the pattern is for short sleeves and she wants me to see if it can be sleeveless. She is very much a plus-size young woman so there are a lot of lumps and bumps to account for! (I`m not looking forward to it) (Also, she doesn`t live nearby so there can`t be many fitting sessions)
It might well be that the armhole (already cut out) is too big for a sleeveless garment. I will discover on Friday when I see her