For clubs and festivals check the Folk Music Map.
Open it in a browser, not 'maps' and select layers required.
https://www.google.com/maps/d/viewer?ll=51.16356355914522%2C-0.11971435546877274&z=11&mid=1d1L8gNDhc6JP84Wyt01-LSEcL_A

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more festival listings
thread.cfm?threadid=162316&messages=10 

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FB page
https://www.facebook.com/groups/sussexfolk or Surrey \ London ... ?