You could contact the Center for Eco-Cultural Studies (CES) in Sri Lanka, located in Colombo and Sigiriya, https://cessrilanka.lk/. They specialize in what you are asking for. I worked with them in 2005 and have been in contact for a long time.
I wrote a 217-page and 141,230-word report to the Center for Eco-Cultural Studies in 2006 after my three-month mission in Sigiriya. I hope my document goes through. I can send you the full report if you can send me an email address.