30k does seem like a quick 'wear-out' for a set of rears - They do bugger all compared to the fronts. Dealers will do the bear minimum when selling cars. It may seem harsh, but their single purpose in life is to make money, so they won't be saying "They'll need pads in 3-4 months time, lets throw a set on for them"!
The good news is though, that you can buy some pads from
www.buypartsbuy.co.uk for £17.18 delivered, & they're an easy DIY, too! - You just need to borrow the special tool to wind the caliper back. (Discs won't be too much, either, in case they're scored).