How to prepare supplementary Self Assessment data
Use this guide in your Britixo workspace. Follow the Self Assessment Data workflow in Britixo to prepare supplementary self assessment data.
Before you start
Required access: Prepare and appropriate approval/submission capabilities. The module must be enabled and its installed version ready for your workspace. Select the intended taxpayer, authority and period before changing a record.
How to prepare supplementary Self Assessment data
- Select Taxpayer, Tax year and HMRC operation, then choose Load operation.
- Read the operation requirements and set HMRC parameters and Filing authority.
- Enter Source / evidence reference and Schema-validated request data for that operation.
- Choose Validate and freeze for review. Open the frozen record in Supplementary filing history.
- Review and approve the exact payload before using the permitted submit action. Open year-end readiness to check its effect.
Controls and limits
- Available operations are governed by the registered HMRC operation and schema; do not invent fields or use another tax year’s payload.
- Recording supplementary evidence does not automatically complete unrelated Self Assessment items.
Check the result
Reopen the affected record and confirm the taxpayer, period, saved values and status. For external actions, inspect the actual authority acknowledgement or settlement evidence; a local saved or queued state is not acceptance.
If you cannot continue
Read the displayed validation or readiness message. Check the module version, role, source scope, authority, period and current approval evidence. If another person changed the record, refresh and review the current version. Give support the screen, error wording and correlation reference; keep passwords, one-time codes and tax identifiers out of public messages.