“[15] As I have recalled, issues of residence may give rise to complex questions of fact. The principles depend on case law not on statutory definition. The Court of Appeal (in Revenue and Customs Comrs v Grace[2009] EWCA Civ 1082 at [6] and [7],[2009] STC 2707 at [6] and [7]) has recently adopted Dr Brice's summary of relevant factors in Shepherd v Revenue and Customs Comrs [2005] STC (SCD) 644 and Lewison J's identification of relevant features in Revenue and Customs Comrs v Grace[2008] EWHC 2708 (Ch) ,[2008] STC 213 . Many of the questions which must be asked to determine questions of residence, such as whether the purpose for which a person has adopted an abode is 'settled' (see[2009] STC 2707 at [6](vi)) or whether there is a sufficient degree of permanence and continuity (see at [6](iv)) lend themselves to no certain conclusion. They require value judgments, which may express a wide range of views, all of which are within the area of reasonable conclusion, even when they conflict. [16] IR20 reminds taxpayers and advisers of this uncertainty, and warns that the Revenue's determination of residence will often depend on its assessment of the facts. The Preface reads: 'The notes in this booklet reflect the law in practice at October 1999. They are not binding in law and do not affect rights of appeal about your own tax. You should bear in mind that the booklet offers general guidance on how the rules apply, but whether the guidance is appropriate in a particular case will depend on all the facts of that case. If you have any difficulty in applying the rules in your own case you should consult an Inland Revenue Tax Office … Some practices explained in this booklet are concessions made by the Inland Revenue. A concession will not be given in any case where an attempt is made to use it for tax avoidance.'”