I bought a metre length of pipe from Millhill Tools.
One size for both lines.
The pipe line without the filter goes to the priming device, and the line from the filter goes to the carburettor.
After thoroughly cleaning the outside of the fuel tank, I carefully inserted the filter through the filler cap and out through the small hole. I then fed the small white ring onto the flexible pipe, packed some silicone silastic sealant around the hole in the tank and pushed the flexible pipe onto the filter's hard plastic pipe. A bit more sealant and that was done.
The pipe that connects to the hole without the filter had sealant placed on the outide 5mm. After inserting into hole in tank, a bit more sealant was added.
You must wait for at least 24 hours before filling tank with fuel.
Steve, April 2010