Architects and Building Contractors in the UK

Im looking for some-one experienced in finding contacts for new business leads / decision-makers for procuring services from consultants. In particular, I am looking for help finding contact details (names and email addresses) of individuals in the Construction sector in the UK (architects and Building Contractors) who would be in a position to procure services from engineering consultants / low carbon for buildings consultants / building services (lighting, heating, cooling) consultants. These would typically be architects or large building contractors.