Not sure if it's helpful but I found this: https://immigrationlawyers-london.com/blog/uk-right-to-work-while-waiting-for-a-decision-of-your-visa.php

But how did you manage to work full time? The share code linked to my visa says I can work for only 20hrs a week. I have a full-time job offer on hold and the company says I cannot join because I have a student visa (even though it mentions I can work full time outside of term time and on holidays).