UKRI Funding Finder
You probably already know about funding opportunities from UK Research and Innovation, you can use their funding search tool to look up current, past and upcoming opportunities. There are a number of different councils that specialise in different areas, but look around - you might find that your research fits funding calls from multiple councils. The councils which are most likely to offer funding for chronobiology are: BBSRC - invests to push back the frontiers of biology and deliver a healthy, prosperous and sustainable future.
MRC - fund research with aim to prevent illness, develop therapies and improve human health. Innovate UK - fund the development and commercialisation of new products, processes and services. NERC - invests in environmental science. Find out more on https://www.ukri.org/ or sign up to their email updates.