It was super convenient being able to pick up and drop off at the north terminal rather than have to shuttle from the south. The Sixt office is inside the Sofitel and they were busy upon arrival but helped us within a few minutes. They politely attempted to upsell me a larger car for an additional 700gbp and extra insurance which I politely declined since the rental already included CDW (collision damage waiver) and they didn’t pressure me any further. I’d recommend booking on the UK website as it seemed to be a better deal than the dotcom site and CDW was included in the price. As it was we got a rather nice newer car but it was a bit bigger that we expected for just the two of us which made parking difficult in someone of the city areas. Not a complaint, just as Americans we should have asked for a tiny car that was easier to park. The only issue we had was that the car decided not to start one day after we stopped for sightseeing probably due to a glitch with the anti theft system. We only had eSIMs in our phone and could not make cellular calls but emailed the Sixt branch to see if they could help. Their response was basically like Jeremy Clarkson saying “oh no. anyway...call the breakdown number” even though we said we could not make cellular calls. Would have been nice if they could have called us via WhatsApp and then connected us to the breakdown helpline. But they wouldn’t. We had to walk a mile to an inn to call with a landline. By the time we went back to the car it decided to start again and the mechanic said they couldn’t do much without a warning light to scan so we just kept going. The car worked fine from then on but we were a little nervous. We did the early dropoff but the spaces were full, thankfully drivalia let us have a space so we could get to the airport. Overall a good trip but Sixt could have been a little more helpful when we were stranded.