Thanks to those who commented on my earlier post, I was very reassured by you all thinking the dress sounded fine. On the what to wear over it front - I just got back from Debenhams having bought
this petite black suit jacket in the sale. It fits *perfectly* which never happens to me, and buttons in exactly the right place for the waist band on the dress. And I'm pretty sure I can get my leather trench coat on over it no problem if the weather is really horrible on Thursday :) It means I'll be wearing black knee high boots rather than my lovely Duo ones but I'm not sure the colour they are really went with the dress that well anyway, given the dress is cafe-au-lait and the boots are dark tan.
So outfit sorted!