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.