Sorry, I glanced at this and jumped to conclusions without properly reading it.
The 40% deliberate, 30% electrical does not surprise me. My instincts are that contractors doing hot work account for more than the report suggests and I've yet to visit or hear about a fire that was caused in an industrial site from a chip pan, smokers materials or candle - not that I am doubting these things do occur, I just think the scope of "non domestic" is wider than the buildings I see, for example I never visit garages or corner shops.
So I'm not doubting or challening the stats, just pointing out that stats probably differ for larger commerical or industrial premises. With fires from heating and contractors featuring more than chip pans, candles and smoking materials.