What's the best medium sized SUV with a petrol engine?

I only do about 6000 miles a year and would like an SUV which would take both a medium and large size dog in the boot. I'm looking at a BMW X3 or Audi Q3. My budget is only about £15k and I'm looking at...

What's the most comfortable medium sized SUV?

We need to find the most comfortable riding, reasonably well equipped small/medium sized petrol automatic SUV for up to £30K and wondered what you recommend?