Your answer depends on your ultimate Antarctic destination.
Your answer depends on where in Antarctica you choose to dock, the speed of your boat and the route you choose.
The route you describe is one route. That would be the probably route to the Antarctic Peninsula. It depends on where in Antarctica you want to go. Another route would be to go to New Zealand from England on one plane, then find other transportation to Antarctica. Finally, if you sailed in a boat, you could go to almost any landing spot on the continent from most anywhere in the world. But that's not a very practical idea, since Antarctic waters are not too navigable.
England is different to Antarctica in being slightly warmer for parts of the year.
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En route, but not that far
Yes, you can.
Depends on your route.
Your answer depends on the route you take to your ultimate Antarctic destination and the speed of the boat.
The flight would be 21 hours long.
Your answer depends on the route you take, your ultimate Antarctic destination and the speed of your transit vehicle.
Your answer depends on where in Antarctica you want to go, and your mode of transportation, plus the route you choose.
Your answer depends on your ultimate destination in Antarctica, the route you choose and the speed of the boat.