The Annual Tax on Enveloped Dwellings was part of a package of measures intended to attack the holding of high value residential property in vehicles which facilitated the avoidance of Stamp Duty Land Tax.
There is also a capital gains charge on residential property disposals which also applies to non-residents.
Various exemptions and reliefs apply but still require a ATED return being filed ordinarily by 30 April each year for the relevant period.
The Sharpe Accountants can do this on your behalf.