Thank you for your reply. I understand that my angle might be tricky, and the dissertation example provided on HO's guidance only covered the compelling or compassionate circumstances where applicant was prevented from returning to the UK from a third country. However, as mentioned in the Oct 2023 ...

My first entry date in the UK was 14 Sep 2016, with a Tier 4 (general) student visa for a one-year pre-master study. Since then, I've continuously stayed in the UK with various long-term visas until 2 January 2020, until leaving outside the UK for travel purposes (the visa expiry date was 21 January ...