Gavin grew up in England and Western Australia and studied English literature in Northern Ireland before embarking on many years of travel, mostly in developing countries, during which he worked as an aid driver in east Africa, as an expedition guide and also scrapping ships on the beaches of India and Pakistan. He also lived in the slums of Nairobi and worked as a teacher for several years, also building clinics and schools with the money he raised as a mountaineer on many fundraising climbing trips. This included six expeditions to climb Mount Everest, a solo walk across the Sahara Desert and a trek to the Magnetic north pole.

He started the adventure travel company Adventure Alternative and the charity Moving Mountains many years ago; the company enabled him to employ many of his friends from the countries where he had lived and worked, and the charity formalised the long term aims of development in many areas of Kenya and Nepal. Both organisations are still running and are still organically growing; most of the employees still work for the company and the charity has given many hundreds of people careers and livelihoods.

Gavin now lives in London with his wife and son, and he still travels and climbs a lot, occasionally lecturing on responsible tourism and small adventures on big mountains. He is also a Fellow of Oxford Brookes University.