I see you have the 1.8NA, which doesn't appear to have the valve that's present on the turbo version. Maybe try to connect a gauge where the fuel line joins the rail? The Rimmer drawing has a push-on connector by the look of it.
https://rimmerbros.com/Item--i-GRID001924
Don't know what the 'rubber sheath' is. Is it the fuel feed pipe?
TC