CG64206 | Private residence relief: tax returns
From HM Revenue & Customs · Capital Gains Manual
There are different return requirements for disposals by individuals and by trustees or personal representatives.
Individuals
no return is required if the disposal is fully relieved from Capital Gains Tax and the acquisition cost of the home is unaffected by gift hold-over relief under the provisions of TCGA92/S260 (see CG67030+).
if partial relief is available, the taxpayer should provide the address of the property sold with a computation of the gain or loss
Trustees or personal representatives
If private residence relief is due on a disposal by either a trustee or personal representative, under the provisions of TCGA92/S225 or TCGA92/S225A, it must be notified (see CG65440 (trustees) and CG65460 (personal representatives) either by rendering a return or as a standalone claim. The guidance for claims can be found in SACM3015 - Making and Amending Claims: How Should Claims be Made - HMRC internal manual - GOV.UK (www.gov.uk)
In most cases an assertion that any gain is wholly relieved need not be challenged and a computation of the gain will not be needed. You should look out for disposals which may not be wholly relieved but should consider whether enquiries are worthwhile in trivial cases.