There are a lot of embedded links to look at to find the database,
here's the direct link to the database as an XLS excel spreadsheet:
http://www.bbc.co.uk/blogs/opensecrets/EPCRegisterData.xlsThat link comes from this article, which is linked to by the article in the OP:
Comparing the energy efficiency of public buildingsMartin Rosenbaum | 09:09 UK time, Tuesday, 25 August 2009
<snip>
However, new regulations came into force a fortnight ago which now allow this material to be divulged.
In response to my request under the Environmental Information Regulations, the Department of Communities and Local Government has sent me
a large spreadsheet (MS Excel, 8.14Mb) listing all the properties on the register, their energy efficiency rating and their CO2 emissions, so that it is possible to analyse this to compare all the buildings on it.
The buildings with the highest operational energy rating are those judged to be the least energy efficient, compared to similar buildings (the average building of that kind should score 100). They are divided into seven bands from A to G, with A the most efficient and G the least.
The data obtained also specifies the buildings' total CO2 emissions. Most of the public buildings emitting the highest quantities of carbon dioxide are hospitals, which may be linked to their large size.