It all started in the early 1970s and the arrival in Britain of "natural gas". As an engineer, he recognised that North Sea gas would pose a safety problem to much equipment that was designed for the traditional "town gas". He saw an opportunity in gas-detection instruments and so left the company he was working for to set up Neotronics with the help of pounds 40,000 raised through taking out a second mortgage on his house and persuading an outside investor to take a small equity stake.
He started in a hut at Stansted Airport, and pioneered microprocessor- based, hand-held sensor systems before becoming a multi-millionaire by selling his controlling stake in what was then a public company to Zellweger of Switzerland in 1996.
But, although he was then in his 70s, he had not finished. An opportunity had appeared a step down the supply chain. Mr Gotley and his daughter, Andrea, set up Alphasense with the aim of designing and manufacturing sensors - in effect the heart of gas-detection equipment.
Ms Gotley, a former draughtswoman, is chief executive and responsible for the day-to-day-running of the new company while her father acts as chairman. Although the company, based in Great Dunmow - just a short way from where Neotronics started, still has a low turnover, it has developed a strong network of buyers of its expertise and technology.
Many of them are in the United States, but this is not problematic, says Ms Gotley. Thanks to e-mail, an employee in a US factory can send a message about a problem to the Gotley team in Essex towards the end of the day, enabling the team to work on it while he or she is asleep and often have an answer by the next day.
Alphasense still has a staff of just 18, but its investment record would put many larger concerns to shame. The idea took an initial year to develop and another year of working alongside manufacturers to be secure and confident of the technology.
"We will always be investing in development," says Ms Gotley, pointing to joint ventures with manufacturers and research links with teams at various British universities.
And with companies such as the GEC division, English Electric Valve and the City Technology Group, a spin-off from City University, also active in various parts of the field, she adds: "Sensor technology seems to be something that we [the British] are good at."