Rather, we decided to split up mainly because we were feeling so claustrophobic from this huge amount of time together, and we were also jaded from so much time on the road. We felt that splitting up would be the best way to inject some new life into things.

So how has it been, walking alone? I have to admit I have felt a renewed buzz about the adventure, and have a new spring in my step. Suddenly, I am not able to rely on Leon for map reading and he has taken the expedition's only smartphone, so I am having to use inaccurate Chinese maps.

This means I not only have to ask for directions far more often, but - because of my propensity to take non-existent paths on shortcuts through the mountains - I am also far more likely to get lost. However, it is nice to know that if I do get lost, while I may have to flounder around (and perhaps feel scared) for hours on a misty, muddy mountain track, I will not have to feel guilty about making Leon walk those extra miles.

On the days when I am on a nice easy road, the hours pass quite differently to when I am with Leon. No longer do they go by quickly in conversation in English. For much of the time, I am left to myself to just think (I really appreciate such thinking time - there is so little of it in normal life), or pray, or listen to my iPod (I try to alternate between music, ChinesePod, and audiobooks).

As a solo walker, my experience of other people has also been different. I am more likely to be invited into village homes - perhaps because as a single traveller I am less like a tourist, and more like a solitary, nomadic dude.

On the downside, I have to do all the talking, which can be exhausting. For example, when I pass through villages, or a passing farmer stops for a chat, I will often have an extremely similar conversation with them. They will ask where I am from, what I am doing and why, why I don't take a car or bus, how old I am, and so on.

The Hong Kong-based hiker and travel writer Bill Purves, on his own walk through China some 14 years ago, described this almost identical round of questions and answers as 'reciting his catechism', which I think captures the experience pretty well. When I was with Leon, we would take turns reciting our catechism, but now I have to answer everyone myself.

On a practical level, my pack is heavier now, because Leon and I both have to carry full camera and production gear (on top of clothes, sleeping bag, and so on). And self-filming is decidedly more tricky.

The other day, after I had been kindly hosted for the night by a little village community buried in the mountains, I set up my tripod and filmed myself saying goodbye to them. Then I turned the tripod to show myself waving to them and walking away on the muddy track. As I set off walking, the whole household started pointing at the camera and shouting at me that I had forgotten it.

So, such self-filming challenges add to the workload, but also to the interest and challenge of being alone.

Leon and I plan to meet up again in Guilin later this week. Then we will have just four weeks of walking as a team, until I return to the bustle of Hong Kong, whereupon the routine of my life as a walker will suddenly seem very distant.

Rob Lilwall's previous expedition, Cycling Home From Siberia, became the subject of an acclaimed motivational talk, a book and a National Geographic television series. Every week in Health Post, he will write about the progress of his latest expedition, Walking Home From Mongolia, which is in support of the children's charity Viva. walkinghomefrommongolia.com