These lights (at £5.99 in LIDL) are great as they take rechargables or standard AAA batteries so not taxking on your leisure battery. Swivel to suit and if you didn't like the silver metallic finish, you could spray them whatever colour you like.
Roller paint your camper at home: http://roller.epizy.com/55554/" onclick="window.open(this.href);return false; for MP4 download.
These are solar powered, two levels of brightness and convert between torch or lamp. A nice ambient light in your van at night. You can even charge your mobile phone off it. £11.99
Cant find any pics, but the petrol stations at Sainsburys are selling "light up lightwsitch" things @ £5. Hard to describe but its basically a battery operated switch that lights up...keep meaning to buy one, maybe today os the day