On the US site of JG Speedfit is a YouTube video showing copper pipe being fitted straight into a speedfit connector. Normally I would stick to copper, being the old fashioned type, but on this occasion, needing to connect a long run under walls and through joists, I used speedfit barrier pipe, connecting to copper pipe with speedfit fittings. Using copper pipe also helps to maintain full bore on a gravity system, whereas using speedfit fittings on plastic pipe requires an insert, which possibly reduces flow. Problems started to appear after a year or so, due to verdigris building up on the copper pipe inside the fitting, causing the fitting to leak. Anyone else experienced this? Speedfit also show a diagram connecting plastic to copper using a copper compression fitting, using their TSM insert, which sounds like a better idea.