What can I wear with this gorgeous Whistles dress (as May Bank Holiday weather is bound to be crap)

[sweetmelody]

This is the dress

Been looking for something to wear to my daughter's christening for a little while and I love it, but the back is quite open and, given the Christening is beginning of May, I'll need something to wear over it.

A cardigan of some description would be easy enough (but a bit dull, I suppose), but I can't get my head around what colour I should wear with it. I am dark-skinned, am an 'Autumn' and love colour. Was thinking of tan shoes/sandals.

Thoughts on colour? Any suggestions more exciting than a cropped cardi?

I'd go with an old gold cropped lurex Cardigan. Something like this but I'm not totally sure about the waterfall front...
http://uk.monsoon.co.uk/view/product/ukcatalog/monn1,mon1.6/8432841252

Or a paler gold which might work better with tan shoes etc. Having a bit of sparkle (but not patterned) would lift the cardigan from being 'meh'.

Otherwise feather or faux fur bolero? Just watch the length at the back...