Herschel Post, chief executive officer of Coutts & Co, dons his walking boots and goes for a stroll with Lynne Maxwell, editor of Country Walking magazine.
It's three years since I last did this walk,' Herschel Post admits.
As we consult our map he finds himself, somewhat ironically, confirming the route to follow with a fellow American, in a setting that is pure England. With wry humour, he adds: 'Talking and walking are dangerous for your navigation.
I define lost in two ways. We are in the right area and we know how to get back to Henley-on-Thames. Roughly translated, that means we are not so much lost as temporarily mislaid.'
Post has his feet firmly on the ground from Monday to Friday as chief executive officer and deputy chairman of Coutts & Co, one of the oldest and leading private banks in the UK. But the man who is in charge of a business with assets estimated to be worth £2.4 billion puts those feet into well-used boots in his leisure time to indulge his passion for walking.
Today we are treading the newly opened Thames Path at Henley on a walk bordering three counties. The Financial Times has been usurped by Walkers' Britain, complete with details of numerous routes.
Post says: 'There's a huge difference between walking and exploring.
When you're walking you have to have some idea of where you are going so that you can enjoy the view. You never know what is going to strike your eye.' He points out a tree with yellowing leaves gilded by an autumn sun by way of illustration. The search for beauty is one of his driving forces. 'I am always looking for beautiful things and it's rare to go on a walk and not find something that makes you feel better for having seen it. It's hard for people who have not walked in a place like the Alps to realise how breathtakingly beautifully it can be.'
In fact, the Swiss Alps are the background for much of his walking with his wife Peggy, also a keen walker, whom he met as a student at Oxford.
'It's absolutely my favourite place. I would just get on a plane and go for the weekend. We go every summer and, after almost 30 years, we have not even come close to exhausting its variety. You get the benefit of Swiss orderliness - all the trails are groomed and marked - and exhilaration.
There are some scary parts, of course, but because it's a marked route you do at least know that at least one other person does not think it's insanity.'
The challenges walking presents lie in climbing ever higher peaks or standing on a glacier, roped together and using crampons. 'You feel you have accomplished something. At work it's different. I was reading in the Sunday Times about a derivatives trader for Morgan Stanley who was saying how you could do a deal and lose a billion dollars. My business is more a question of building something - adding a good person to the team. You do not get the precipices you find on a mountain. It can be tremendously stressful but you can't flip a coin and lose it all overnight.'
He continues with the analogy. 'I would not want to climb Everest; I'd rather climb an equally beautiful mountain where I was more in control.
I've never thought of walking as an activity which gives you the thrill of doing something that other people can't. People sometimes ask why we keep going back to the Alps, to the same place. My answer is that no walk is the same twice.'
Returning to the question of work, one of the attributes of any successful manager, he feels, is to have a good sense of humour. 'Work should be fun. You have to look forward to going in each morning and feel at the end of the day that you like working in the place. And the main reason I go walking is to have fun. I would have made a very bad Calvinist or Victorian clergyman. They certainly would not be walking on a Sunday afternoon.
They would have been contemplating their Maker.'
The one absolute no-no on a walking expedition is to think about work.
'It's a wonderful way to forget everything I have been doing all week.
If something has caused tension or made me angry, by the time I have walked for two or three hours it has all gone. Walking is an antidote for the stresses in your job and puts the rest of your life into perspective.'
We hear the weir before we see its spectacular stretch. 'Success,' says Post. 'It's not raining, and we are not lost.'.