I've finally found one that ticks all the boxes, it's vibrant, ever-so-slightly metallic, it has a hint of violet and the formula is great. It's Cosmic Blue from Avon's upcoming Nailwear Pro+ line.
It's good to go in two coats and dries really quickly. I've only had it on for two days but so far the wear seems pretty great too! They are meant to last up to 12 days... a pretty bold statement! I'll be interested to see if they live up to it.
Avon sent me a selection of shades from the new line and to be honest most of the others are pretty basic colours (there's a black, red, various shades of pink etc). This is the only colour that got me excited, but I think the formula is great so if you're looking to stock up on essential colours then these might be a good line to look at.
They won't be available till the 10th May, but are quite a bargain at £6 each.