I bought one of these
www.ebay.co.uk/itm/APRICOT-maxi-dress-purple-floral-size-XS-/261229687772?pt=UK_Women_s_Dresses&hash=item3cd280b3dc
from New Look last year.
It is just the job for me. I'm usually a size 14, but have crept up to a 16 (hopefully not for long). It has short sleeves so I don't have to readjust it constantly, and hides bra straps while it also covers my upper arms, which I am self conscious of.
It is v necked, which is good as I have a fuller bust, but is then nipped in to make the most of the waist I do have.
It's pretty plain and quite a dark colour. I've had lots of compliments wearing it and am hoping to find something similar. I'd love it if anyone on here can point me in the right direction.