Empty homes statistics have to be buit up from a variety of sources - the government doesn't provide a full dataset. The key sources are the Council Taxbase returns (CTB0 and the Local Housing Statistics returns.
The charity Empty Homes has taken data from these two sources to build their own more inclusive dataset. This is cited in the Commons Library Standard Note on Empty Homes.
Look out for the small print, such as the fact that exempt homes in some categories are counted as short-term empties. That's because there is no information available about how long exempt homes are empty. They have also had to make some assumptions about vacant housing assocation supported housing units.
Historic datasets from EHA are now no longer available and this web-page now hosts only the latest report. Reports sience 2015 are discoverable however and can be found in our library under titles following the format: Empty Homes in England 2017 - EHA report