fuel filler neck

Hello all. My J-reg Classic has a leak from a hole in the filler neck. Unfortunately this bit seems to be listed as 'obsolete' and not available. Scouring the web seems to indicate that the Discovery 1 fuel tank is identical...would a Disco neck work?? (I was asked by one parts company where the fuel flap is: up near the window or halfway down the panel...its up near the window)
Is the fuel filler neck repairable if bit can't be had??
Living in hope!

Don't know if this will help.

http://www.roverparts.com/Parts_Catalogs/Range_Rover_Classic_Parts_Catalog/PDF/RRC8_Page09.pdf

Thank you!

Could you buy a longer hose between tank and filler and hacksaw rotten bit off?

Have got what I think is the right filler neck...has anyone replaced this bit? is it difficult?

If I remember correctly, you just lever the rubber off at the top end

thank you