Probably a reference to HMRC & Grace or Grace and HMRC depending on whose appeal was where. The question was whether Grace was resident in Britain not whether he was domiciled. Double taxation wasn't a feature of the case perhaps because the South African SARS weren't involved.
HMRC publish guidelines to residence which can be a major factor in determining tax status.
http://www.hmrc.gov.uk/international/rdr3.pdf The world is littered with people who interpreted HMRC rules to suit themselves. Gaines Cooper springs to mind as an ace loser.
The only sensible advice is to spend a little money and get the advice of a professional tax adviser from a reputable firm. Be warned also that what is the rule one day is not the next in Britain where instability in the tax regime is inherent.