Most airlines now charge for seat selection in advance, unless you have certain level of loyalty points. That’s works if you fly frequently with the same airline or alliance. Going to Zimbabwe I have always flown Emirates as they also fly from Birmingham. Also cheaper too. Not this time, it was cheaper to drive to Heathrow, park and fly with Ethiopian, no brainer. The generous luggage allowance too. The flight crew was professional and friendly. Meal time though I was offered a choice between beef and chicken, the flight attend didn’t have the chicken on her trolley. I had to wait ages to get it, that’s the only gripe.
The overall journey time is not bad and you get to Harare mid afternoon.