And finally, my search is over. Models Own has a wide range of sparkly nail colours that are super easy to apply, last for ages - I've been wearing Emerald City for a week - and only cost a fiver. Get, as they say, in. My nails are very distracting when I try to type, but make me happy every time I look down at them.
Buy it online from the Models Own website or from some branches of Boots and River Island.

