Do you think the 26kw model of the Viessmann vitodens-w 111 storage combi would be more suitable to a 12 radiator property as DHW was the main issue which led to the high end 35kw combis?
http://www.plumbnation.co.uk/site/viessmann-vitodens-111-w-26kw-storage-combi-boiler/
http://www.plumbnation.co.uk/site/viessmann-vitodens-111-w-26kw-storage-combi-boiler/