Adding (T1OO) abbreviation in text to help explain the concept in the graph later on.

Author: Cotswoldsmaker

docs/type-one-opt-outs.md

@@ -1,7 +1,7 @@
 ## Background
 
 The OpenSAFELY platform was established during the COVID-19 pandemic; the legal basis the platform originally operated under was for the monitoring and control of communicable disease and other risks to public health.
-NHS England policy was that the [Type 1 Opt-Out](https://www.nhs.uk/using-the-nhs/about-the-nhs/opt-out-of-sharing-your-health-records/) [[archived here](https://web.archive.org/web/20250401015716/https://www.nhs.uk/using-the-nhs/about-the-nhs/opt-out-of-sharing-your-health-records/)] was not required to be upheld due to the overriding public interest in responding to the COVID-19 pandemic.
+NHS England policy was that the [Type 1 Opt-Out](https://www.nhs.uk/using-the-nhs/about-the-nhs/opt-out-of-sharing-your-health-records/) [[archived here](https://web.archive.org/web/20250401015716/https://www.nhs.uk/using-the-nhs/about-the-nhs/opt-out-of-sharing-your-health-records/)] (T1OO) was not required to be upheld due to the overriding public interest in responding to the COVID-19 pandemic.
 In June 2023, the [legal basis for the operation of the platform](https://digital.nhs.uk/about-nhs-digital/corporate-information-and-documents/directions-and-data-provision-notices/data-provision-notices-dpns/opensafely-covid-19-service-data-provision-notice) [[archived here](https://web.archive.org/web/20250414105355/https://digital.nhs.uk/about-nhs-digital/corporate-information-and-documents/directions-and-data-provision-notices/data-provision-notices-dpns/opensafely-covid-19-service-data-provision-notice)] changed to powers that traditionally _do_ uphold a Type 1 Opt-out.
 Therefore, since June 2023, the OpenSAFELY platform has been required to exclude patients with a Type 1 Opt-out from all projects, except those explicitly described in our [Data Access Policy](data-access-policy.md) and [Data Protection Impact Assessment](https://digital.nhs.uk/about-nhs-digital/corporate-information-and-documents/directions-and-data-provision-notices/data-provision-notices-dpns/opensafely-covid-19-service-data-provision-notice#further-information).