Heppel, 70, is leaving the famous New Spitalfields Market in Leyton, east London, on a positive note as he looks forward to his retirement and reflects on his career in the fresh produce industry.
"The industry is fascinating," he said. "I fell in love with it when I first joined. My only complaint is that I did not know it was there when I left school." On leaving school, Heppel first set his sights on a career in the Royal Navy. Travelling was second nature to him - he was born in Venezuela and his father worked for oil giant Shell.
The family returned home to Britain in 1946 and lived in South Shields, Tyne and Wear, for six months before moving to Scotland, then north Wales and then London.
Heppel attended the HMS Conway naval training school in Wales. While working for the navy he saw an advertisement for a job as committee secretary for the National Federation of Fruit & Potato Traders - the predecessor to the Fresh Produce Consortium - and never looked back.
"The industry is very social," he said. "It's got a lot of great characters and I have enjoyed every minute of it."
During his time at Spitalfields Heppel helped to engineer one of the largest changes in the market's 300-year history - its relocation in 1991 from the City of London to the purpose-built 12.5ha site in Leyton.
He told Grower that the market's location has secured its future because it remains easy for lorries travelling from the continent to take the M20 in Kent to head into the capital. As for the future of the market, Heppel said traders would like to join the other City of London wholesale markets - Smithfield and Billingsgate - and possibly relocate to the Olympic Park after the 2012 games.
"What the traders would like to see is a complete market here in east London. The three markets could sit together on the Olympic Park site. If that happens the environmental benefits would be huge - all of the green lights in the world would light up."
He added that the market will "always be there" for British growers - even though many of them in the past couple of decades have turned their back on wholesale customers in favour of supermarkets.
"They saw supermarkets as the future," Heppel recalls. "But now they are becoming disillusioned with them and for many reasons are coming back to wholesale markets. They are coming back."
Heppel has many plans for his retirement, including learning to paint and playing bowls. " I am passionate about my flat green bowling and took on the position of chairman at my local club," he said. "I have a bit of work to do in terms of recruitment."
Janet Hutchinson, whose husband Chris is chairman of the SMTA, is the association's new chief executive after working on the market for trader Arthur Hutchinson for many years.
She said: "It's an exciting challenge because Jim's a hard act to follow, but I've had quite a lot of involvement with the market over the years so it was an easy decision for me to make."