London gatwick airport

Long since designated the worst in the UK, is updating the tram between terminals. How long do you think this should take? A few weeks? A month or two, during slack season?

No. Six months. For six months, if you are foolish enough to fly from the north terminal, and use public transport to get there - a bus has been laid on.
A slow, smelly, overcrowd bus. One with a long queue.
Nice. Easyjet and virgin are unaffected.