Just before the No7 vouchers stopped, I picked up one of these: a Stay Perfect Eye Mousse in the colour Pewter. These are a 5ml mousse-like cream shadow, which comes in six shades (all quite subdued and wearable tones) to create a light sheer cover of pigment.
Like Urban Decay Primer Potion, not much is needed to create even coverage on your eyelid, but you can build up layers for a higher pigmentation. It also works well as an eyeshadow base. It is prettily shimmery and sheer when worn alone. I don't usually wear cream eyeshadows but make an exception for this one! They retail at £9 each from Boots - so I may wait until No7 vouchers are re-issued before experimenting with the other shades!