Got the link to this website today and thought I'd add it here. Not sure if anyone has already added this, so I'm sorry in advance if this is the case.
I'm not completely certain how the reawrds work, it mentions vouchers for high street stores and UK attractions. A £10 welcome bonus and £10 every 3 months there after. I know it's not for everyone, as not everyone will have a compatible phone, but worth mentioning, even if just a few of you act on it :o)