However, he admitted that the programme - which divides new store developments into six categories of Urban Lifestyle, Neighbourhood Affluent, Neighbourhood Value, In Transit, Community Supermarket and Daily Needs - still needed further tweaks in some areas.
Speaking at Spar's recent annual congress in London, he said that work was continuing to refine the product range at the Urban Lifestyle store in London's Haymarket. Despite this, sales for the first month after launch were up 25%.
Trials will continue through the rest of the year with a full rollout expected during 2007.
Meanwhile, Spar will run the first of three bursts of national television advertising next month on the theme of 'Surviving Summer', to coincide with the rollout of its new marketing strapline 'There for you'. The second ad burst will coincide with British Food Fortnight in September and October and the third will run for two weeks in December.
Marwood also promised to focus on local sourcing as an area that independent retailers could use to really beat the multiples. He said that many Spar stores were already doing this by offering up to 10% locally sourced products compared with multiples where local produce made up 1-2% of the offer.
The group is also developing a new mystery shopping programme, which it says is necessary in light of increased competition. Spar said that the format would place a greater focus on customer service.