Extended Reports extension: missing custom data field in the report template

[cristina-p]

Our non-profit is using the Extended Reports CiviCRM extension, but would like to add some custom fields to the report "Extended Report - Contributions Detail with extra fields" - CRM_Extendedreport_Form_Report_Contribute_DetailExtended class.

The built-in report already displays certain custom data fields of a data set used for Individuals, as you can see in the following screenshot:

But one of the fields on this data set is missing "Are you a UK Tax Payer and would you like to Gift Aid your donation?", even though is searchable, as you can see in the following screenshot .

Could you please advise me how I can display this missing custom data field "Are you a UK Tax Payer and would you like to Gift Aid your donation?" in the report template?

Many thanks in advance for your support.