It was the same people, long journey on motorbikes, experience of a lifetime, (but different journey- down through Europe and Africa, rather than around the world).
The word order has been inverted (auxiliary +subject + verb clause)
1 If the first journey had not been such a success, they never would have considered the second.
2 If he had been a more experienced rider, he might not have fallen so often.
Had they known how difficult the journey would prove, they might never have started.
Not only did The Long Way Round journey challenge their view of the world, it also tested their physical endurance
Never before had they experienced such hospitality from complete strangers.
scarcely: /ˈskeəsli/ used to say that something happens immediately after something else happens. E.g. He had scarcely put the phone down when the doorbell rang. Scarcely had the game started when it began to rain.
1 Seldom have I seen him looking so miserable.
3 Under no circumstances should you leave the office.
4 Had we known there would be a water shortage, we would have been more prepared.
5 Only later did she realise her mistake.
8 Were they to have apologised more quickly, I might have forgiven them.
1 Not until they were ready to depart did he think about leaving his family.
2 Only then did I see the danger that we were in.
3 No sooner had we left the tent than it collapsed.
4 Had we thought about it more, we would have taken extra fuel.
5 Never before had they ridden motorbikes for such extended distances.
6 At no point did they consider giving up the expedition.