The majority of doctoral students are not funded by UKRI, especially in the Arts, Humanities, and Social Sciences. It is also worth remembering that It is the institution that awards your doctorate, not your funding body. However, UKRI is more than a funding body, and HEIs in the UK take significant guidance from UKRI in the development of their own policies. So it is always a good starting point for information about funding rules, regs and general guidance. https://www.ukri.org/news/coronavirus-impact-on-ukri-supported-research/
It is immediately clear that you are expected to keep working if possible, from home, and if this is to be a short period, then extensions to funding periods should not be applied. It is also clear that you are expected to consider and develop alternatives to your original plans to allow you to continue your research.
UKRI has said that extensions can be considered where “self-isolating undermines a student’s ability to finish their doctorate” or there has been the “Postponement of critical activities where alternatives are not available... for example due to departmental or institution closures. To avoid unnecessary pressure on students, extensions to submission dates should be awarded.”
Even with this UKRI guidance, you and your supervisor may have to navigate some complex and in some cases, contradictory advice, as not all funding bodies will issue identical advice. This is annoying and frustrating, but in these unusual times, you will are not alone. Remember to communicate with your supervisor and your faculty/ school/ doctoral centre administrators. Your supervisor may have less experience and knowledge of the particular funder’s guidance as they should only have a handful of doctoral students at any one time, whilst administrators will have experience of many more.
If you are self-funding, you may be tempted or panicked into thinking that there is no guidance for you or that you can do whatever suits you best. Your institutional rules and regulations still apply to you. If you are part of a small department or an institution where numbers of doctoral candidates are very small or specific services are poorly developed, UKRI is still a good starting point for understanding what is being expected of their funded research students during this crisis period. You can use this as a starting point for your discussions with your supervisors.
If you have become ill for any reason (sorry to hear that), you should follow your funding body’s Terms and Conditions. UKRI is accepting “ any revised Government guidance regarding medical certification.” Don’t wait until you become ill to investigate the terms and conditions of your funding and if you are self funding, investigate claiming government support during illness. Government advice is not always easy to understand https://www.gov.uk/, especially as this is an evolving situation, but start with your department or institutions guidance, and take it from there.
So, this might not have been what you wanted to hear, but keep going, at home if possible, keep communicating and stay safe.