Both found jobs. Both took a 25 per cent pay cut.
He left school and home at 16 and said he was lucky a chef took him under his wing "and made me go to school and get all the qualifications".
He worked at Simon Gault's first restaurant, Bell House in the Auckland suburb of Howick, and in Hawke's Bay worked at Bradshaw Estate Winery and Wine Country Motor Lodge before trainingchefs at FutureCol, which was not what he expected.
"You are more a social worker than a teacher."
Wanting to get back into the industry, he took a job as national franchise manager for the Breakers Restaurants chain.
There were good franchisees operating, including Hastings' Breakers and Bar which Mr Withnall bought.
"It was owned by the landlord at that stage and wasn't making a lot of money. I could see what they weren't doing right and, when the opportunity came along, I grabbed it."
Under his direction, business steadily grew.
"We built a market with a consistent product. The other part is yelling about who we are - we didn't take out small ads - and we've continued to be loud."
Regular specials are the lifeblood of the restaurant, beer the lifeblood of the bar.
Success was volume-based, the volume came because of value. On Sunday, there is roast and dessert for $14.95.
"We aim to menu with many different parts. Its seven daily specials have proved popular. Many customers come in six days a week or every Sunday at the same time.
"We have the potential to sell 200 meals but with that we can sell 200 drinks and 200 sauces."
Diversity is a major feature of his clientele.
"When the opera house was open we could have a lady in diamonds at a table while a guy plays pool with his kids, his patch turned inside out."
Mr Withnall admits a success factor is the lack of competition in the Hastings city centre. He doesn't expect any soon.
"The reality is you would have to spend about $800,000 to recreate something like this and the investment would need a return."
He recently invested $100,000 in the formerly-unused upper floor of the building and the Hastings Conference Centre was quickly booked for every Saturday from October to the beginning of February,mainly for wedding receptions and family functions.
Other diversifications have not succeeded. Serenity Foods catered for funerals but he said inaccurate perceptions of the brand contributed to its demise.
Restaurant turnover has doubled but his salary hasn't.
"I haven't paid myself for three years."
Surplus was spent on improvements.
"We have constantly changed the look of the place - it's an ongoing process - and obviously upstairs will be changed as well.
"Success is about investing back into the business."
Mr Withnall recently returned from an "ideas" trip to the United States and Europe, looking at hundreds of bars and restaurants.
It was always easy to spot the owner for a chat.
"They are the ones that position themselves where they can oversee what's going on in the establishment - keep an eye on staff, customers and the bar."
He does the same at Breakers, "watching staff interact with customers and diners' faces when they try the food".
Mr Withnall was overseas when Breakers recently won the Supreme Award for Business Excellence at the Hastings City Business Awards, also winning the Ngatarawa Wines Excellence in Food & Beverage Award.
In previous years, it has won the Best Franchise Award.
Judges said business strengths were good community engagement (it has wide sponsorships), strong systems, good customer knowledge, a strong marketing plan and food systems for consistent delivery of product.
"Outstanding business that continues to grow, setting himself an aspirational target of $3 million.
"Simon has an impressive management structure.
"He has [an] annual strategic review with management. Great systems in place for client service and food standards," the judges said.
Mr Withnall said it was "a real thrill to win the big one".
"It is great recognition of the investment we've made."
Wife Rebecca received the business award on his behalf, shortly after the manager at Ravensdown had spent several weeks at the Harvard Business School.
Hard work is something the family of four children know plenty about. They often eat at the restaurant if they wish to see their father.
"I was raised with the idealism that sacrifice and hard work will get you where you want to go," he said.
