just pop em out of the clips underneath, then drag the lines out of the chanel in the chassis leg from underneath. the channel is nice and smooth inside ts o fuel line swap isnt hard at all.
you may have to drop tank a bit to get the other ends out if its not a gti, there are clips between the body and tank holding lines up which are a bugger to undo with tank fitted. lift the boot carpet and you'll see a metal disc, take that out and you'll have access to the level sender and can release the lines from there before you drop the tank