I've bought lots of Joe Browns in the past (not in the last 6 months), and generally they are true to size, though I am about DD/E bust. I've had a few tops that were not generous in the bust
The quality though is variable. I have a cord pinafore which is fab but some of the prints dont wash well and very quickly look faded. Jackets and coats go bobbly quite quickly. So as someone said...as a £30 dress you wouldn't mind.
When Ive bought bigger ticket items I buy from one of the catalogues that give 25% off with first purchase have exhausted them all now