Originally Posted by OttoMH

I live in Europe and travel back to the U.K. frequently. When my UK passport was at an embassy for a Visa I used my Mex one to get in to the UK which is 90-day visa free entry. Nowadays there is no exit stamp, the exit is registered by API data on the flight. I booked my return in the wrong name so was worried I might get flagged as a Mex-overstay. Next time I was in I approached the agent and explained the situation and he registered the Mex out and the U.K. In.