I spied this long-sleeved shift dress in French Connection yesterday. I think this looks great for something smart to wear in the evenings. It comes in 6 different combinations of colour and embroidery.
The sleeves are sheer, so not quite perfect for you if you want to keep your arms completely covered, but great if you don't mind showing a tiny bit. Another great thing about this dress for the more modest dressers is the high neckline, and the embelishments around the neck and cuffs mean the only accessories you'll need to wear are earrings.
Complete the look with tights or leggings and a pair of heels!
This dress is available from French Connection for £130