Magnum

It's a 1.4 engine. The DS3 was a manual

I recently bought a used 2015 Audi A1 S Line (petrol) with circa 4000 miles on the clock. I drive in London in varying road/traffic conditions with the occasional motorway run, however I'm finding the fuel efficiency to be very poor. In my Citroen DS3 I was averaging around 55mpg, however I'm getting around 32mpg from the A1. I drive in Efficiency mode and as it's an automatic transmission it's not like I'm driving in the wrong gear. My foot is not particularly heavy on the acceleration pedal and nothing has changed in my style of driving or the kind of journeys I'm making. In addition I'm finding that the petrol gauge pin drops significantly after short journeys. For example in the attached pictures you can see the difference after only a 12 mile journey. Any ideas on how this can be improved? I don't have air con constantly running etc by the way. And is this quite typical fuel usage from an A1?

If I buy a used vehicle with 7000 miles on the clock and the servicing schedule is every year/10000 miles, do I have to service after driving 3000 miles (I.e when the clock shows 10000 miles) or 10000 miles from the point that I take ownership from the dealer?