The store is intended as a blueprint for company-owned and franchised Spar stores across the UK.
Henderson Retail has already secured a site but said the planning process was "cumbersome" and it was considering converting an existing store instead.
Ron Whitten, finance director, said: "We hope the store will be trading by 2008. We will use it to test self-checkout and electronic shelf-edge labelling. The best ideas will be used for the development of our own stores and we expect some will be shared with the wider Spar estate in the UK." The store will be one of Henderson Retail's largest, at 6,000 sq ft.
Henderson has secured a further 12 stores this year. Eleven belong to independents, but the other it has purchased, taking its company-owned total to 52.
Henderson plans to secure a further eight company-owned stores within a year. Two are in the pipeline.
In February, Henderson Group announced it had earmarked £18m to invest in company-owned sites.