Here are details on the UK Equality Act 2010 outlining the duty to make reasonable adjustments (from Citizens Advice Bureau):

https://www.citizensadvice.org.uk/law-and-courts/discrimination/what-are-the-different-types-of-discrimination/duty-to-make-reasonable-adjustments-for-disabled-people/

Here are articles from Elizabeth's website on pacing yourself during recovery from illness & long covid
 

https://www.elizabethturp.co.uk/phdi/p1.nsf/supppages/6083?opendocument&part=9

and articles on how counselling can help people adjusting to disability

https://www.elizabethturp.co.uk/phdi/p1.nsf/supppages/6083?opendocument&part=6

and here is an article with advice for freelancers balancing the challenges of work and illness

Working Through Illness as a Freelancer (allfreelancewriting.com)