I also have some lovely DM's, so this is a possibility 
I would, I hope, be wearing it "ironically" as another poster suggested. The dress itself is very conservative, but can be changed for the better with the right accessories I believe.
If it was in Primark for £20 I would have already bought it! I don't care where it comes from. Cheaper the better!
The shoes are gorgeous in real life. They are 100% staying.