It already faced Tesco. With Asda's arrival on the Northern Ireland scene, the ­Henderson Group faces another big, aggressive supermarket. And M&S also is doing well with its Simply Foods format. Yet ­Henderson, a wholesaler and retailer, is making a very good fist of it. Sales for the calendar year are expected to exceed £250m, up from £232m, and profit margin will be up from 2.2% to 2.4%.

MD Martin Agnew attributes the improvement to several factors, but in particular an increase in large-format stores. Two launched in the past month and two more come on stream this year, bringing the total to 14.

On the retail side, the group has also made progress, with an increase from 50 to 54 stores operating under either the Spar or VivoXtra formats. And Henderson has also seen good growth in its property business. The Business Development Partnership leases out sites to retailers looking to get their foot in the door. Sales are up 50%, with 10 new leaseholders on stream. And they are tied into contracts with the Henderson wholesale operation.

This innovation has been particularly important as like-for-like sales across the group have halved from 6% to 3%. Agnew blames the arrival of Asda and Tesco's withdrawal from several shopping centres and subsequent move to standalone facilities.

Henderson continues to protect its 400 wholesale clients with selective investment, which has helped purchasing loyalty increase from 50% to 55%.

Agnew also credits an increase in TV advertising. "We are using deep-cut promotion to grow volume." And it's innovating in other ways, too. In Ballyhackamore, east Belfast, Henderson is competing with a Tesco ­Express and M&S Simply Food, which is reportedly bringing in £170k per week.

But neither has adversely affected the Henderson store and trading is up from £47k to £50k per week, thanks to a new in-store Subway and Post Office.