It should be quite straight forward, turn off the fuel with the isolator if fitted,
cut the hose inside the console, cut the tie rap around the collar and tape the new hose to the existing hose making sure of a good connection, coat the new hose with fairy liquid or vaseline and pull the hose through from the back.the new hose should find its way through quite easilly, If you feel it getting to tight pull it back a bit from the consul end and try again.
At least if the two hoses get seperated youve allways got the draw string as backup. I shall be doing similar with mine this week, fitting the new plotter and sounder.make sure you go for 10mm fuel hose. Good luck.