Computing the amount to assess: business changes: changes in scale, nature or location of trade: relocations
A relocation is a particular change in the nature of a trade. Some businesses, especially some professions, are carried on wherever the proprietor happens to be and are not fixed to a particular locality. Examples are entertainers and professional sportspersons with a national or international reputation and practising barristers. Other businesses are ‘local’ in the sense that the business is done in a particular place (Seldon v Croom-Johnson  16TC740 at page 746).
The relocation of a local business, if substantial enough in nature, will give rise to the permanent discontinuance of one trade and the commencement of a new and different one (Fry v Burma Corporation Ltd  15TC113 at page 128).
The most relevant factor will usually be the extent to which the customer base of the trade changes.