".....Probably this is a dumb question, but can anyone tell me how many
litres of paint I need to paint one side of six fence panels, each panel is
6 x 6 feet, the overlap type panels? ......."

If you are going to use one of the many types of coloured timber
preservative then read the tin.
They all have different coverage.

--
David Hill
Abacus nurseries
www.abacus-nurseries.co.uk