The new trollies cannot be taken outside at the back of Mercadona, the wheels lock. Don't know about the front car park. So I had to carry all my shopping, bag by bag to the car, leaving the rest in the trolley and the car wide open until all had been loaded into the car. What if you had a wheelchair and trolley or a child in a pushchair? Surely they could have put the automatic lock on at the kerb.